Is a disabled person myself I found true working with my society that you can exercise very effectively without using whatever part of your body is a problem that day. using a chair to do your weight lifting it may not be the 200-pound you lift a day but you could lift 10 pounds setting. Just keep going.
Walking a little everyday would help you maintain your freedom and mobility. Even if all you can manage is a short 5 minute walk. And you may be able to stop any further decline in your vad foot and recover some strength if you are able to invest a little time in getting fitted for a good pair of suppotive footwear that target your specific problem.
Yoga is a great way to exercise without killing yourself. There are a huge variety of types to try, each of which caters to different levels of mobility & general fitness. There's even such a thing as chair yoga which doesn't require using the feet at all.
Finally, you could try a simple circuit training routine at home. There are now a huge amount of free fitness routines available either as online videos, or through dedicated fitness apps. These cater to all levels, are great for exercising at home, and can be used to target specific issues or parts of the body e.g posture improvement or muscle toning.
I don't know your conditio, so hard to say if exercise will do good for your foot, but in general (even for artrosis, excersise will lighten the pain and losing weight can slow down artrosis and reuma big time).
Just try the free apps and skip those with jumping ect. But planking, abs, arms, weights and stretch bands should be fine.