My experience with a treadmill is that whilst it is great to control the speed and terrain for your walk, I suffered enormously the next day with having trainers on and the impact of walking on my feet.
The neuropathic pain in my feet the next day is quite severe. It doesn’t show up at the time, it is a delayed reaction, apparently quite common.
Dr. Parry recommended water based exercise, like aqua jogging — easy and effective, rather than impact.
Also, this Zumba stuff is quite good. Here where I live, instructors are offering free classes for elderly people and people with disabilities — and altering the program to fit. So, people in chairs, etc. still get some benefit from the exercises.
I have tried it and it is really fun, and definitely gives you a workout. Don’t know if you can find something similar where you are….
I also use resistance bands (very cheap) and you can do strengthening exercises for your legs as part of a routine.
Cheers and good luck