So I thought about switching to LightDM. I switched by doing
sudo systemctl disable sddm sudo systemctl enable lightdm
Then I restarted arch linux and everything ran fine. But then I thought about getting a better looking display manager. So I uncommented the line in /ect/lightdm/lightdm.conf that says this:
I can't remember exactly what was there. Now, I think that I didn't install that theme, because when I booted up arch linux, it says "cannot boot light display manager" or something like that. However, I can't figure out how to access the terminal. If I get the terminal, I can just change back the display manager or re-comment that line. How do I fix this? All I need to do is access the terminal and then I'm good to go, but I can't seem to figure out how.