In Norcal - non-san francisco area, they can be a 4.0 on a weak team. San Francisco has a lot of players who don't have kids so they can play a lot of tennis and are very very good. So a 4.0 there can be pretty good.
you have good tennis skills. but you looked injured.
in my experience, 3.5 to 4.0 has a huge range of players. usta rating is not science. it's bad american maths.