Since I was like 12 I was blessed with the genetics of an 80 yo. Having muscle spasms, hernias, and all sorts of bizarre crap. The two times in my life I got into a workout regime things would get progressively better until months down the line, when I'd have to do surgery of some kind, likely because I 'worked out too much'. Doctors tell me to start lifting weights, but they don't seem to believe me and simply tell me I'm a male and young and shouldn't be as frail as I am. No tests in 20+ years have shown anything out of the ordinary, except for whatever problem I developed all of a sudden, so it's no wonder. I'm afraid that trainers in a gym wouldn't be any better. Got no idea where to start. Pool workouts with the elderly maybe?
I think you might have some luck if you call physical therapists in your area for gym/trainer recommendations.
You also don't have to disclose too much if you don't want to when it comes to hiring on a trainer. If you let them know you have a condition and that it will affect your limits in your workout, they might be able to offer workout plans that could help your body type. You can explain your range of motion, weight thresholds, and how you want communication to go.
I think if you speak with a gym manager or one of the senior employees, they should be able to match you to somebody familiar with strength exercises/routines that don't tax you too much.
Let them know what you want ahead of time. I have a shitty elbow, so I specifically told them I didn't want the pep talk to get me to do another rep when I wasn't feeling it. My 'no' is final at the gym and I don't want somebody to ignore my limits for the sake of doing that little bit more.
I'd also ask about clothing or other gear that would help navigate working out.
And of course, if you're not feeling safe or the vibe isn't right, you're allowed to take a step back from the workout, the trainer, or even the gym. I wish you luck in finding a fitness plan that works for you!