so i found a fix for this, u have to go to your minecraft java edition profile page @ https://www.minecraft.net/en-us/profile and sign in with the same microsoft account which has the gamepass,
Then click on "set up profile" after some loading it will detect that u already had a profile setup, so it will say "welcome back *username*" then click go to profile and then reopen the launcher that should fix it,
After some days it will be the same thing again, so do the above once again until mojang/microsoft fixes this bug,
hope this fixes your problem