Im actually gonna try to double down on this recommendation after re-reading that you also have joint issues. Step 1 of each of the 'big 6' is picked with this issue in mind and tend to describe them as good "therapy" excercises for people recovering from injury/surgery/illness/etc.

I'm not saying this guarantees you'll be able to work up to one armed push ups (im still mountains away from that feat myself) but if regaining joint strength/durability is one of your main areas of focus, id very strongly recommend at least skimming through the 1st step or 2 in each of the big 6.

It's also got a chapter on self coaching, which ive found very useful to revisit every now and then