Ubuntu no longer boots after reinstalling graphics driver

Ubuntu-Version: 22.04 or 22.10, can't check anymore

I started my machine today and discovered that the desktop environment wasn't loaded. I got some text which seemed to indicate ubuntu services starting, then it disappeared and I had a black screen with a blinking cursor. I was able to switch to a terminal with ctrl+alt+f3. After some googling and some digging around I ran sudo lshw -c video and saw the word unclaimed next to my graphics card, which I understood as the graphics driver not working. So I did a sudo ubuntu-drivers devices and picked the recommended driver, which was as I recall nvidia-driver-520-open. So I tried to install it with sudo ubuntu-drivers install nvidia-driver-520-open. It reported that all drivers were already installed. So I figured I could reinstall with apt: sudo apt-get install --reinstall nvidia-driver-520-open (I think, I'm writing this from memory). Then I rebooted, and got the same again. After some more googling, I find a post suggesting I need to install the linux-headers for the kernel version So I did sudo apt-get install linux-headers-5.17.0-1020-oem(again - version from memory) and rebooted again. And this time I got the gnome login screen and was able to log in. However I found in the ubuntu settings that the selected grahics card? was llvmpipe. So I tried selecting the nvidia graphics card using sudo prime-select nvidia and rebooted again. This changed nothing. So I thought I might have to try a different version of the driver. I went to "Software & Updates" > "Additional drivers" and selected the 515 version of the driver. After the installation was finished I rebooted. However now I can no longer really boot. I get some text which I assume to be kernel logs, then I get a black screen with the cursor again, but this time I cannot switch to a terminal. After retrying several times, I got gnome again, but the screen turned black a few seconds after logging in and it went unresponsive.

I am able to boot from the usb drive I used to install ubuntu

I realise that I've probably been an idiot here, but is there any way I can fix this?

1. Boot, as the "BIOS" text appears, hit ESC once
   (If that does not work, try holding down either SHIFT key)
2. ... that should make the "grub menu" appear.
3. Under the "Advanced" option, find "Recovery mode" for your latest kernel version and select it.
4. Yet another menu should appear; select options fsck, enable networking and then drop to root prompt, hit Enter to actually get to the # prompt - i.e. Bash as user root.
5. Here you may do many things freely, i.e. destroy your Linux - so be thorough with what you type.
6. dpkg --list | grep ^ii.*nvidia will tell which nvidia related packages are installed.
7. do sudo apt purge package-name on all of it,
8. then do reboot and see if you can log in normally...
9. If yes; hit Super-key (Win-Key) and start typing Additional drivers, quite soon a greenish icon will appear; click on it / select it and hit Enter. Install an older nVidia driver and see if that works (I'm using 470)
10. if no; get back to the recovery mode root prompt and attempt to install e.g. version 470 of nvidia-drivers from there... type apt install nvidia and hit TAB at that point; a list of available drivers should appear; type the first char of one and hit TAB again... then with the full name, hit Enter to attempt install.
    (keep an eye on if there are any errors while installing! Try to revert such an installation with "purge" above)