I haven’t used Ubuntu in a bit, but I’m decently familiar with linux overall. Looked up a guide. It indicated you could install LXDE with sudo apt install lxde
and then reboot. The guide said that LXDE should be the default Desktop Environment now, because it’s the most recently installed one. If for whatever reason LXDE isn’t the new default, on the Login screen, in the upper left corner there should be a dialogue box to select whichever Desktop Environment you want as the new default.
https://vegastack.com/tutorials/how-to-install-lxde-on-ubuntu-22-04/ This is the guide I was using, if it helps. I’d take a look at section 1, step 2, where it shows the picture of the “Configure LightDM” menu. I think it’s probably not too bad, but I’d be curious to hear how it goes.