I would install it with docker (moreover docker compose) preferably. Easier to maintain and troubleshot. Anyway, for 1, make sure jellyfin has the rights to see your video and music folders. For 2, are you trying to do it from the same network or from outside?

Maybe take a look at paperless-ngx, it will take care of the OCR for you and make it searchable. Just not sure if it will show the path correctly.

If you are inside, the GPS location might not be found. If happing outside, it could be because of a bad configuration of the systems settings.

You can already put your PC games on romm and your saves. You just download the game in gog and put it in romm in the windows or Linux platform (I think there is one for mac games also). If you already have romm installed, it might be easier to use it than to have a second service installed.