Games not getting downloaded

I've also had issues similar to this before when I had one copy of a game on the internal memory and another copy on an external or on my SSD. I always double check to make sure I don't have multiple copies of a game downloaded/installed by accident.

you may want to try clearing the games locally cache and any of the games files than restart your Xbox than put the disk in and if it is a game where you may play it halfway through don't just let it download

That makes sense. The thing that confused me the most was somehow the disc based game is 5gb bigger than the digital version. I'll still have my character won't I?

Your save file should be in the cloud.

You should uninstall the game from gamepass. It is a digital game which you can no longer play so you are now required to install the disc based game.