I already have a topic for Manjaro KDE. I wanted to try Manjaro XFCE to see if it would work, and I think it has a slightly different issue. I edited the grub menu by adding splash, noapic, nolapic, nomodeset, and systemd.mask=tlp.service, plus I switched all [graphics driver].modeset=1 to [graphics driver].modeset=0
I think the last edit is necessary, because when I tried booting without it, the screen went black instead of showing information.
When the screen did show information, I saw an "Error No UMS support in radeon module" followed by a lot of text, followed by "Failed to start Lightdm". I pressed Ctrl-Alt-F6, logged in, and ran the following commands:
$ sudo pacman-mirrors -f3 $ sudo pacman -Syyuu $ sudo pacman -S lightdm lightdm-gtk-greeter lightdm-gtk-greeter-settings $ sudo systemctl enable lightdm $ sudo lightdm $ systemctl status lightdm.service
The second to last command also failed. The last command showed the following (roughly):
lightdm.service: Main process exited, code=exited, status=1/FAILED. lightdm.service: Failed with result 'exit-code'. lightdm.service: Service restart job, restart counter is at 5. Stopped Light Display Manager. lightdm.service: Start request repeated too quickly. lightdm.service: Failed with result 'exit-code'. lightdm.service: Failed to start Light Display Manager.