Accounts pane does not appear (iMac G4)

When booting up my family’s old iMac G4, everything works fine until the point when the accounts pane where you choose your username and enter your password should show up. From there, it’s stuck with no way to do anything— although volume adjustments, mouse movement, etc. still works. The dead-end screen is pictured below.

I’ve tried resetting the PRAM, booting in safe mode, etc. No luck with anything. I know our old accounts and files are still there as I’ve seen them listed in single user mode. I’ve tried all sorts of stuff including tricking it into thinking it’s new / factory reset (everything worked just fine while setting up a new account as if just out of the box, but once done with basic setup I got stuck in the above screen yet again.

I’ve tried lots of other things within single user mode as well. This is one of those tricky issues to solve just by googling, since there are many issues similar to this but with small details varying. Any solutions/tips you can provide would be greatly appreciated! Thanks!

Oh yeah, in case this matters: I noticed that in single user mode, the prompt to type a command is * sh-2.05a# * rather than * :/ root# * which is what I’ve seen in most of my research. So that feels significant.

K thanks! :)