I’m wondering if I need my disc in my system at all time while playing
Well, if you bought the physical version you need it for DRM purposes, although once the game has launched that disk is no longer accessed. I think if you eject the disk while the game is running, the system will basically quit the game? Not sure that’s something I’d want to risk (chance of file corruption).
Leaving the disk in while playing shouldn’t be a problem for the disk itself; just make sure you quit and then eject the disk before doing something else or shutting the console down. My XB1 doesn’t always realise there’s a disk still in there when I start up again, which has led to some awkward moments.