I realize this is a similiar question to weird behaviour after installing nvidia 361 driver but I don't even get far enough (anymore) to try the answer posted there. I'm not too familiar with the terminology of Ubuntu, this happened on my second day of using it.
Edit: TLDR Version here:
I installed the nvidia 535 driver, rebooted, and system did not boot anymore.
I tried getting into the GRUB Menu / CLI to try some fixes, but the keyboard behaviour is messed up, basically making writing or even navigating the menu not really feasible.
Letting it boot normally USED to bring me to a purple screen. CTRL ALT F1 does not open a terminal here. Also the monitor loses connection after a couple seconds here.
Now it boots to something which I'm not sure what its called. It displays some log. Doesn't seem to be accepting keyboard inputs before the monitor turns off.
Long Version: I installed a nvidia 535 (it also said something about open kernel) driver from the Ubuntu "Driver Manager". Upon reboot, the system would show a purple screen with only the Text "Ubuntu 24.04" displaying somewhere (though this is NOT one of those "help i see a black/purple screen what do" questions)
I tried to get into GRUB Menu (The one where you see the OS you can boot in a menu) but it disappeared basically instantly.
I found answers telling me to increase the timeout-number via a terminal that you should be able to boot up with CTRL ALT F1 on even the blank screen. This terminal does NOT appear on my purple screen. Also it should be noted that the monitor loses signal and does not regain it after about ~10 seconds on this purple screen.
On subsequent reboots it got really weird, because the behaviour changed nearly every time. Some times the grub menu would stay on screen, sometimes it would disappear again really quickly, sometimes it would boot to some kind of CLI with a log of some kind (not the GRUB CLI where you go when the GRUB Menu times out), and sometimes it would tell me "Environment Blocked by secure boot" (this might have been only the case when holding ESC to boot up with GRUB, I can't really replicate it anymore)
Also it should be noted that even in the GRUB Menu and GRUB CLI, my keyboard inputs were messed up. I got an arbitrary number of registered button presses per actual button press (tap a, get anywhere between 1-3 a's, for every button, including backspace), which is why I had a very hard time trying to implement any solutions utilizing GRUB CLI that I found. All of the inputs were also REALLY laggy and delayed.
On the few last attempts, I had glitchy screens and it went to the aforementioned CLI with logs, which is not the GRUB CLI that comes after the GRUB Menu, and I dont know what to do from there.
I want to get the system into a position where the boot behaviour is not random and my keyboard inputs work properly, so I can actually get into the GRUB Menu again to try some of the solutions on this site.
This is a a sidenote, I did some stuff like download the CUDA toolkit amongst other things before all of this happened, in case that matters.
