If there is not enough space on the hard drive, you may encounter the Call of Duty Vanguard not launching PS5 issue. So, you'd better check and free disk space on the PS5 system. You can access the Settings menu from the Home screen and navigate to Storage, and then delete all unnecessary game cache, add-ons, and apps.
The PlayStation 4 Standard Edition will have an option to upgrade to a digital version for PlayStation 5 through the PlayStation Store. Please note: The PlayStation 4 disc must be inserted into the PlayStation 5 to access the digitally upgraded PlayStation 5 version of the game.