Sharing your games doesn’t lock your entire library when someone is playing a different game than you in the same account.
We’ve been using it since it came available to test, and is such a lovely change from before. The check out system is so much cleaner than the old locked out of account while someone in the family is playing.
Also, you can share DLC now which is nice. I believe the old system if your share partner has the same game but without the DLC, you can’t share the DLC with them. Now they can play your version with the DLC.