I got lucky, I'm still using the same Titanium Backup version of this app and it works on Android 10 for me. I re-install the back-up, grant root permissions and then I close it. Once I open it back up it's at the Main Menu.
This has always been one of my "must-haves". There's a few apps I love to use fullscreen on. Anyway, I hope another app/hack that's similar comes along someday that was as reliable as this one was. I loved this app.
would you like to share that Titanium Backup file? I used to back up this application, but it was deleted.