The repository does not have a Release file

Question

I have installed a .deb file which wasn't compatible with my machine, then I have deleted the repo from software & updates, but still I'm getting the error as you can see below, I have tried this solution, but it didn't work in my case!

can you please recommend to me a solution please? thanks in advance.

$ sudo apt update
E: The repository 'file:/var/nv-tensorrt-local-repo-ubuntu2004-8.5.2-cuda-11.8  Release' does not have a Release file.
$ cat /etc/apt/sources.list
deb cdrom:[Ubuntu 20.04.2.0 LTS Focal Fossa - Release amd64 (20210209.1)]/ focal main restricted
deb-src http://archive.ubuntu.com/ubuntu focal main restricted #Added by software-properties
See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
newer versions of the distribution.
deb http://fr.archive.ubuntu.com/ubuntu/ focal main restricted
deb-src http://fr.archive.ubuntu.com/ubuntu/ focal multiverse main restricted universe
Major bug fix updates produced after the final release of the
distribution.
deb http://fr.archive.ubuntu.com/ubuntu/ focal-updates main restricted
deb-src http://fr.archive.ubuntu.com/ubuntu/ focal-updates multiverse main restricted universe
N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
team. Also, please note that software in universe WILL NOT receive any
review or updates from the Ubuntu security team.
deb http://fr.archive.ubuntu.com/ubuntu/ focal universe
deb-src http://fr.archive.ubuntu.com/ubuntu/ focal universe
deb http://fr.archive.ubuntu.com/ubuntu/ focal-updates universe
deb-src http://fr.archive.ubuntu.com/ubuntu/ focal-updates universe
N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
team, and may not be under a free licence. Please satisfy yourself as to
your rights to use the software. Also, please note that software in
multiverse WILL NOT receive any review or updates from the Ubuntu
security team.
deb http://fr.archive.ubuntu.com/ubuntu/ focal multiverse
deb-src http://fr.archive.ubuntu.com/ubuntu/ focal multiverse
deb http://fr.archive.ubuntu.com/ubuntu/ focal-updates multiverse
deb-src http://fr.archive.ubuntu.com/ubuntu/ focal-updates multiverse
N.B. software from this repository may not have been tested as
extensively as that contained in the main release, although it includes
newer versions of some applications which may provide useful features.
Also, please note that software in backports WILL NOT receive any review
or updates from the Ubuntu security team.
deb http://fr.archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://fr.archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
Uncomment the following two lines to add software from Canonical's
'partner' repository.
This software is not part of Ubuntu, but is offered by Canonical and the
respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu focal partner
deb-src http://archive.canonical.com/ubuntu focal partner
deb http://security.ubuntu.com/ubuntu focal-security main restricted
deb-src http://security.ubuntu.com/ubuntu focal-security multiverse main restricted universe
deb http://security.ubuntu.com/ubuntu focal-security universe
deb-src http://security.ubuntu.com/ubuntu focal-security universe
deb http://security.ubuntu.com/ubuntu focal-security multiverse
deb-src http://security.ubuntu.com/ubuntu focal-security multiverse
This system was installed using small removable media
(e.g. netinst, live or single CD). The matching "deb cdrom"
entries were disabled at the end of the installation process.
For information about how to configure apt package sources,
see the sources.list(5) manual.
deb https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2004/x86_64/ /
deb-src https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2004/x86_64/ /
deb https://librealsense.intel.com/Debian/apt-repo focal main
deb-src https://librealsense.intel.com/Debian/apt-repo focal main
deb https://dl.winehq.org/wine-builds/ubuntu/ groovy main
deb-src https://dl.winehq.org/wine-builds/ubuntu/ groovy main
deb https://dl.winehq.org/wine-builds/ubuntu/ focal main
deb-src https://dl.winehq.org/wine-builds/ubuntu/ focal main

Edit

$ grep -r deb /etc/apt/sources.list.d/
/etc/apt/sources.list.d/graphics-drivers-ubuntu-ppa-focal.list:deb http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu focal main
/etc/apt/sources.list.d/graphics-drivers-ubuntu-ppa-focal.list:# deb-src http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu focal main
/etc/apt/sources.list.d/docker.list.distUpgrade:deb [arch=amd64 signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu   focal stable
/etc/apt/sources.list.d/bazel.list:deb [arch=amd64] https://storage.googleapis.com/bazel-apt stable jdk1.8
/etc/apt/sources.list.d/nvidia-container-toolkit.list.save:deb [signed-by=/usr/share/keyrings/nvidia-container-toolkit-keyring.gpg] https://nvidia.github.io/libnvidia-container/stable/ubuntu18.04/$(ARCH) /
/etc/apt/sources.list.d/nvidia-container-toolkit.list.save:#deb [signed-by=/usr/share/keyrings/nvidia-container-toolkit-keyring.gpg] https://nvidia.github.io/libnvidia-container/experimental/ubuntu18.04/$(ARCH) /
/etc/apt/sources.list.d/ros2.list.save:deb [arch=amd64 signed-by=/usr/share/keyrings/ros-archive-keyring.gpg] http://packages.ros.org/ros2/ubuntu focal main
/etc/apt/sources.list.d/teams.list.save:deb [arch=amd64] https://packages.microsoft.com/repos/ms-teams stable main
/etc/apt/sources.list.d/bazel.list.distUpgrade:deb [arch=amd64] https://storage.googleapis.com/bazel-apt stable jdk1.8
/etc/apt/sources.list.d/teamviewer.list:deb [signed-by=/usr/share/keyrings/teamviewer-keyring.gpg] https://linux.teamviewer.com/deb stable main
/etc/apt/sources.list.d/teamviewer.list:# deb https://linux.teamviewer.com/deb preview main
/etc/apt/sources.list.d/teamviewer.list:# deb https://linux.teamviewer.com/deb development main
/etc/apt/sources.list.d/nodesource.list.save:deb [signed-by=/usr/share/keyrings/nodesource.gpg] https://deb.nodesource.com/node_18.x focal main
/etc/apt/sources.list.d/nodesource.list.save:deb-src [signed-by=/usr/share/keyrings/nodesource.gpg] https://deb.nodesource.com/node_18.x focal main
/etc/apt/sources.list.d/ros-latest.list:deb [signed-by=/usr/share/keyrings/ros.gpg] http://packages.ros.org/ros/ubuntu focal main
/etc/apt/sources.list.d/checkra1n.list.save:deb [signed-by=/usr/share/keyrings/checkra1n.gpg] https://assets.checkra.in/debian /
/etc/apt/sources.list.d/ubuntu-toolchain-r-ubuntu-test-focal.list:deb http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu focal main
/etc/apt/sources.list.d/ubuntu-toolchain-r-ubuntu-test-focal.list:# deb-src http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu focal main
/etc/apt/sources.list.d/teamviewer.list.save:deb [signed-by=/usr/share/keyrings/teamviewer-keyring.gpg] https://linux.teamviewer.com/deb stable main
/etc/apt/sources.list.d/teamviewer.list.save:# deb https://linux.teamviewer.com/deb preview main
/etc/apt/sources.list.d/teamviewer.list.save:# deb https://linux.teamviewer.com/deb development main
/etc/apt/sources.list.d/ros-latest.list.distUpgrade:deb [signed-by=/usr/share/keyrings/ros.gpg] http://packages.ros.org/ros/ubuntu focal main
/etc/apt/sources.list.d/robotpkg.list:deb [arch=amd64] http://robotpkg.openrobots.org/packages/debian/pub focal robotpkg
/etc/apt/sources.list.d/nodesource.list:deb [signed-by=/usr/share/keyrings/nodesource.gpg] https://deb.nodesource.com/node_18.x focal main
/etc/apt/sources.list.d/nodesource.list:deb-src [signed-by=/usr/share/keyrings/nodesource.gpg] https://deb.nodesource.com/node_18.x focal main
/etc/apt/sources.list.d/nvidia-container-toolkit.list:deb https://nvidia.github.io/libnvidia-container/stable/ubuntu18.04/$(ARCH) /
/etc/apt/sources.list.d/nvidia-container-toolkit.list:#deb https://nvidia.github.io/libnvidia-container/experimental/ubuntu18.04/$(ARCH) /
/etc/apt/sources.list.d/ros-latest.list.save:deb [signed-by=/usr/share/keyrings/ros.gpg] http://packages.ros.org/ros/ubuntu focal main
/etc/apt/sources.list.d/cuda-ubuntu2004-11-6-local.list.distUpgrade:deb file:///var/cuda-repo-ubuntu2004-11-6-local /
/etc/apt/sources.list.d/ubuntu-toolchain-r-ubuntu-test-focal.list.save:deb http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu focal main
/etc/apt/sources.list.d/ubuntu-toolchain-r-ubuntu-test-focal.list.save:# deb-src http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu focal main
/etc/apt/sources.list.d/teams.list:deb [arch=amd64] https://packages.microsoft.com/repos/ms-teams stable main
/etc/apt/sources.list.d/ros2.list.distUpgrade:deb [arch=amd64 signed-by=/usr/share/keyrings/ros-archive-keyring.gpg] http://packages.ros.org/ros2/ubuntu focal main
/etc/apt/sources.list.d/docker.list.save:deb [arch=amd64 signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu   focal stable
/etc/apt/sources.list.d/bazel.list.save:deb [arch=amd64] https://storage.googleapis.com/bazel-apt stable jdk1.8
/etc/apt/sources.list.d/ubuntu-toolchain-r-ubuntu-test-focal.list.distUpgrade:deb http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu focal main
/etc/apt/sources.list.d/ubuntu-toolchain-r-ubuntu-test-focal.list.distUpgrade:# deb-src http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu focal main
/etc/apt/sources.list.d/graphics-drivers-ubuntu-ppa-focal.list.save:deb http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu focal main
/etc/apt/sources.list.d/graphics-drivers-ubuntu-ppa-focal.list.save:# deb-src http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu focal main
/etc/apt/sources.list.d/robotpkg.list.save:deb [arch=amd64] http://robotpkg.openrobots.org/packages/debian/pub focal robotpkg
/etc/apt/sources.list.d/checkra1n.list:deb [signed-by=/usr/share/keyrings/checkra1n.gpg] https://assets.checkra.in/debian /
/etc/apt/sources.list.d/docker.list:deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu (lsb_release -cs) stable
/etc/apt/sources.list.d/nv-tensorrt-local-ubuntu2004-8.5.2-cuda-11.8.list.save:deb [signed-by=/usr/share/keyrings/nv-tensorrt-local-9A139056-keyring.gpg] file:///var/nv-tensorrt-local-repo-ubuntu2004-8.5.2-cuda-11.8 /
/etc/apt/sources.list.d/ros2.list:deb [arch=amd64 signed-by=/usr/share/keyrings/ros-archive-keyring.gpg] http://packages.ros.org/ros2/ubuntu focal main
/etc/apt/sources.list.d/teams.list.distUpgrade:deb [arch=amd64] https://packages.microsoft.com/repos/ms-teams stable main
/etc/apt/sources.list.d/nv-tensorrt-local-ubuntu2004-8.5.2-cuda-11.8.list:deb [signed-by=/usr/share/keyrings/nv-tensorrt-local-9A139056-keyring.gpg] file:///var/nv-tensorrt-local-repo-ubuntu2004-8.5.2-cuda-11.8 /
/etc/apt/sources.list.d/teamviewer.list.distUpgrade:deb https://linux.teamviewer.com/deb stable main
/etc/apt/sources.list.d/teamviewer.list.distUpgrade:# deb https://linux.teamviewer.com/deb preview main
/etc/apt/sources.list.d/teamviewer.list.distUpgrade:# deb https://linux.teamviewer.com/deb development main
/etc/apt/sources.list.d/robotpkg.list.distUpgrade:deb [arch=amd64] http://robotpkg.openrobots.org/packages/debian/pub focal robotpkg