APT seems broken in my Ubuntu

Question

I am a beginner in Ubuntu.

Just last week I have installed Ubuntu18.
I have a dual boot machine on new laptop with Secure boot switched-on (Windows 10 and Ubuntu 18.04.5).

I have NVIDIA GeForce GTX 1650 in my laptop, so I tried to install Nvidia drivers by following the steps mentioned here: https://gist.github.com/bitsurgeon/b0f4440984c9e60dcd8fe8bbc346c029

But now, neither the NVIDIA driver is installed, nor my apt seems to work. Whenever I try to install something using sudo apt install <package-name>, I get this error constantly.

$ sudo apt install aptitude:i386
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 aptitude:i386 : Depends: aptitude-common:i386 (= 0.8.10-6ubuntu1)
                 Depends: libapt-pkg5.0:i386 (>= 1.1) but it is not going to be installed
                 Depends: libboost-filesystem1.65.1:i386 but it is not going to be installed
                 Depends: libboost-iostreams1.65.1:i386 but it is not going to be installed
                 Depends: libboost-system1.65.1:i386 but it is not going to be installed
                 Depends: libcwidget3v5:i386 but it is not going to be installed
                 Depends: libncursesw5:i386 (>= 6) but it is not going to be installed
                 Depends: libsigc++-2.0-0v5:i386 (>= 2.8.0) but it is not going to be installed
                 Depends: libsqlite3-0:i386 (>= 3.6.5) but it is not going to be installed
                 Depends: libxapian30:i386 but it is not going to be installed
                 Recommends: libparse-debianchangelog-perl:i386 but it is not installable
 libnvidia-gl-450 : Depends: libnvidia-common-450 but it is not going to be installed
 libnvidia-gl-450:i386 : Depends: libnvidia-common-450:i386
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).

It seems my apt is broken, how do I fix this? As suggested above, I have tried to run sudo apt --fix-broken install, but I get this warning:

$ sudo apt --fix-broken install
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Correcting dependencies... Done
The following packages were automatically installed and are no longer required:
  g++-6 libaccinj64-9.1 libcublas9.1 libcudart9.1 libcufft9.1 libcufftw9.1 libcurand9.1
  libcusolver9.1 libcusparse9.1 libnppc9.1 libnppial9.1 libnppicc9.1 libnppicom9.1 libnppidei9.1
  libnppif9.1 libnppig9.1 libnppim9.1 libnppist9.1 libnppisu9.1 libnppitc9.1 libnpps9.1
  libnvblas9.1 libnvgraph9.1 libnvidia-common-450-server libnvrtc9.1 libnvtoolsext1 libnvvm3
  libthrust-dev libvdpau-dev ocl-icd-opencl-dev opencl-c-headers python3-debconf
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
  aptitude:i386 aptitude-common libapt-pkg5.0:i386 libboost-filesystem1.65.1:i386
  libboost-iostreams1.65.1:i386 libboost-system1.65.1:i386 libbz2-1.0:i386 libcwidget3v5:i386
  libgcrypt20:i386 libgpg-error0:i386 libgpm2:i386 liblz4-1:i386 liblzma5:i386 libncursesw5:i386
  libnvidia-common-450 libsigc++-2.0-0v5:i386 libsqlite3-0:i386 libsystemd0:i386 libudev1:i386
  libuuid1:i386 libxapian30:i386
Suggested packages:
  aptitude-doc-en:i386 | aptitude-doc:i386 apt-xapian-index:i386 debtags:i386 tasksel:i386
  libcwidget-dev:i386 rng-tools:i386 gpm:i386 xapian-tools:i386
Recommended packages:
  libparse-debianchangelog-perl:i386 apt:i386
The following packages will be REMOVED:
  apt apt-utils skypeforlinux ubuntu-desktop ubuntu-minimal ubuntu-release-upgrader-gtk
  update-manager update-notifier update-notifier-common
The following NEW packages will be installed:
  aptitude-common libapt-pkg5.0:i386 libboost-filesystem1.65.1:i386 libboost-iostreams1.65.1:i386
  libboost-system1.65.1:i386 libbz2-1.0:i386 libcwidget3v5:i386 libgcrypt20:i386 libgpg-error0:i386
  libgpm2:i386 liblz4-1:i386 liblzma5:i386 libncursesw5:i386 libnvidia-common-450
  libsigc++-2.0-0v5:i386 libsqlite3-0:i386 libsystemd0:i386 libudev1:i386 libuuid1:i386
  libxapian30:i386
The following packages will be upgraded:
  aptitude:i386
WARNING: The following essential packages will be removed.
This should NOT be done unless you know exactly what you are doing!
  apt
1 upgraded, 20 newly installed, 9 to remove and 1 not upgraded.
9 not fully installed or removed.
Need to get 6,130 kB/6,140 kB of archives.
After this operation, 295 MB disk space will be freed.
You are about to do something potentially harmful.
To continue type in the phrase 'Yes, do as I say!'
 ?] 

Without knowing the consequence, I shouldn't change things, thus I am asking here if somebody could point out what to do. Or if there is a good tutorial on apt, so that I could understand how it works and how I can fix my problem.

Looking for to every solution.

Edit:
Output of uname -a:

$ uname -a
Linux mehta-hp 5.4.0-52-generic #57~18.04.1-Ubuntu SMP Thu Oct 15 14:04:49 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

Output of gedit /var/log/apt/history.log: https://paste.ubuntu.com/p/knfP2rhVbQ/

Output of apt list --installed: https://paste.ubuntu.com/p/G2tTz3v26b/