EDIT: I kinda solved it by installing Wayland (on my Nvidia card, Ouch!) to replace Xorg. Not sure if this is gonna last though. Perhaps Manjaro is the one I'm gonna throw out FIRST if anything happens from now on.
What should be the first line of defense? Timeshift?
This happened after I installed AUR package masterpdfeditor and 2 applications from github (some hashing algorithm programs, I think they were "Dilithium" and "Latice-based-cryptography-main", one of them was provided by NIST.)
If using GUI: I login, black screen for few seconds, then back at login screen.
If going to ctrl+alt+f2, login successful, then startx, see picture provided (higher quality).
I tried adding a new user, but result is the same.
I have a live usb to do the Timeshift. (I can also chroot if necessary... But I'm not extremely professional)
If that's what you think then you don't understand why people complain about manjaro. It's the 1 week package delay to "ensure testing". There have been bugs that were released in arch and a week later in manjaro, no fix nothing. Also, if you use manjaro and the AUR, which they promote as a possibility, you might have a versioning issue where the AUR package expects packages a week faster than manjaro gets them, and that can actually, very easily, break your system.
Endeavour IS arch but not arch with a shiny wrapper and a shiny forum, that's good, Manjaro is NOT that.
EOS is basically arch but has some packages of theirs that are pulled from their repos, but every other package comes directly from arch, any update comes from arch and so on. They basically reinstall some utility programs and leave you to your devices, no bullshit.
If you want to compare Eos to anything, try garuda, those two are very similar to my understanding.