A possible workaround if this issue will appear on your single player session…
Today i had exactly the same issue @Eradicati0n mentioned on my ps5 single player session. I had an infinite loading screen. This problem is not the first time that happened to our console, we had it on age of sorcery chapter one, too. Back then i deleted 3 years of gaming on single player and i managed to log in by starting new game. Today i did something different, i logged in to my alternative account in the same console and started a new game in this account by deleting the progress of this account. Of course it worked and this account successfully logged in the single player session. So i turned off the game, switch to my main and connected normally to my single player session.
So if you stumble in this issue, just start a 'new session on an alternative account and your main session will be healed!