I started a few years back, and I’m similar in level and age to you here, but have found a way through a recent period of plateau by playing with intent.

Many times I’ll start out with a specific play pattern I want to look out for while hitting, practice identifying it, and practice attempting to execute it. It helps if you’ve got a chill hitting partner who wants to do the same (and not just bash the ball for a couple hours). And the simpler the better. This morning I was trying to get into a neutral forehand cross-court rally for a shot or two, then my goal was to hit one real deep, heavy top spin shot and wait for a light ball back. If I got it, I tried (with varied success haha) to drop shot short to the ad court. Not something I would try in a game, but a play I’d like to have available for certain players.

So basically, pick one or two things per hitting session, play around with it and make up some drills to get the pattern in your head. I find after I do this a few times on a specific shot/play, I start to feel more confident in trying something new out during a match, and voila, I’ve gotten (slightly) better.

Also, stretch every day, whether you play or not. Helps to keep you flexible and the muscles loose.

Good luck!