My moms lung Dr told her to exercise her lungs also. This was done by blowing up a Ballon daily. While setting and watch TV. Really helped with the ability to exercise. She did treadmill
The seated bike with arm pull on it. The water wheel
And just walk the track around the gym. If you don't have the gym access. Just walk at home.
Do small 3 pound waights.
Above head and out to side of waist.
Setting in a chair if needed.
Do leg lifts out in front of you .
You can do back kick standing while holding a chair for balance.
Would ask your Dr before doing it. I did these with my mom just for low I pact work out to lose weight. Have bad knees
Good luck with your journey

Prayers 🙏🙏🙏

This sounds more like something your doctor should answer. But I am sure there are plenty of low impact type of exercises that would not put too much strain on your lungs. Just walking is great exercise. And one most doctors recommend. Can take it slowly and see how you do.