Everyone,
just a suggestion - would everyone still experiencing Photos problems please log their problem via the Apple Support page (for their country). The feedback forum problems don't always make it to Apple engineers.
I logged a new Catalina problem in Feb 2020 and Apple fixed it for most users but not in my case. Apple closed the job as complete and because I still had the problem I thought they had just ignored it. When I talked to Support on the phone this week (Sept) we all realised that some users, like me, still had a problem. The Photos problems have been fixed for most users but not all. Apple Support needs a "kick along".
Go to the Apple Support site for your country (https://support.apple.com) select Mac, MacOS, go to the bottom right of the page, select "Want to talk with someone?", select "Applications & Other Software Topics", select "The topic is not listed", enter a detailed one sentence description of the problem, and request to talk to someone at Apple Support.
If Apple request your machine's serial no. and say it is no longer supported then request an exception (since Catalina is new and buggy).
Talk to Apple Support. Be polite but firm.
Oh, and good luck.