It sounds like you need a knee replacement - maybe both? Has anyone suggested that? I have no idea if that’s even possible for you. My wife has had both hips replaced and when you say “even heavy meds don’t work”, I’ve seen that first hand when she needed them replaced.
The recovery and rehab for knee replacements are harder on folks than for a hip replacement, but I spent Saturday walking around a large flea market area with a friend who had both knees replaced within the last year, and he said he’s pain free.
A pool is good. An exercise bike is good, and they can usually be found for a few bucks at a garage sale. I had knee surgery once (not replacement, just a “clean out”) and they had me on an exercise bike within 4 days. You can set the resistance to next to nothing, just moving your legs is the benefit.
Also, as @Mnketo46 said, just losing weight is going to help.
Whichever, all the best to you, and saying a prayer for you.