After installing newest NVIDIA driver, Ubuntu 22.04 will not boot ("Finished: wait until snapd is fully seeded")

Question

I own a Dell XPS 8960, which comes with a NVIDIA RTX 4070. The XPS came with Windows, but I used a Bootable USB to wipe Windows and install Ubuntu 22.04 instead.

Tonight, I wanted to install CUDA. Here is everything that I did following up to the issue:

• sudo apt update then sudo apt upgrade then sudo apt autoremove.
• nvidia-smi to check the driver versions.
• sudo ubuntu-drivers devices to check for the recommended NVIDIA driver version.
• sudo apt install nvidia-driver-535 to install the recommended NVIDIA driver.
• sudo reboot now

The reboot sent me to a screen filled with tiny lines, the last of which said "Finished Wait until snapd is fully seeded". The screen turned black after a while, and nothing else happened.

Here is everything I have tried to fix the issue of my computer no longer booting. Again, note that I am on a computer that originally came with Windows, but was later wiped and replaced with Ubuntu 22.04.

• From the comments on this answer, I deduced that I would need to set nouveau.modeset=0 in /etc/default/grub.
• To do the above, I tried to boot into the root shell. I tried everything listed in this answer, but nothing worked (it all still went to the "Finished Wait until snapd is fully seeded" screen).
• I read that I could try booting into Recovery mode. I tried to do so following the instructions from this question, which instructed me to go to the GRUB Menu. However, even though I tried everything to get into the GRUB Menu (which would have an option saying "Advanced options for Ubuntu"), it didn't work. Below is what I tried to get into the GRUB Menu:

  • Pressing F2 got me into Boot Options (which listed ubuntu, Onboard NIC (IPV4/6 PXE) under "UEFI Options", and BIOS Setup, Diagnostics, and BIOS Flash Update under "OTHER OPTIONS").

  • Pressing F12 got me into BiOS.

    • The boot order in BiOS seems to be correct; the first priority is called ubuntu. Secure Boot is disabled as well.

  • Holding SHIFT did nothing.

  • Repeatedly pressing Esc gave inconsistent results; I think it depends on when I pressed it.

    • A few times, there would be a flash of what looked like the GRUB Menu, but then it'd go back to the "Finished Wait until snapd is fully seeded" screen. In fact, I've found that pressing Esc would switch between that screen and the Dell logo as my computer was trying to boot up.
    • Once, I got to a weird shell that said "GRUB" at the top, and also said GNU Grub: Minimal Bash-like line editing is supported. Remembering the first question I had seen, I entered the command nouveau.modeset=0 and pressed enter. The terminal appeared to accept it, and nothing happened.
      • Then, I restarted the computer. This sent me to SafetyAssist, which is a Dell program that scans for hardware/software errors. It appears that entering that command did something really bad. In the end, the software said "No bootable devices were found", and suggested that this was likely caused by a corrupt drive or by an incorrect boot order (and I had already checked the boot order and believed it to be correct).

I truly thank you for taking the time to read this question. Does anyone know how I can fix this, and, perhaps, why this happened?

(The only possible thought I have for why this may have happened: I didn't purge all NVIDIA-related files before trying to install the driver. The tutorial I read didn't mention it, but later tutorials I found did)