The latest version of Simple Google Maps is compatible with Drupal 10, so I guess this issue can be closed as 'works as designed'.
I've uploaded what I've done so far to https://gitlab.com/reswild/opigno-lms-d10/ but there's still some work to be done before it installs cleanly.
If you just want a soft fork, this might not be all that much work, as you can use the existing Opigno modules either as-is, or with just some minor patching. I did some testing this weekend with updating Opigno 3.1.0 to run on Drupal 10, and while it got a bit tedious sorting through compatibility issues and other minor errors, I haven't run into any major problems so far.
My main issue when testing Opigno has been that it is too difficult to customize, so if someone wants to make a fork that is a bit more modular and customizable, I might be up for helping out with this.
This appears to be a duplicate of #3037306: Upload file is required. →
The patch in that issue worked for me.