Congratulations on getting better and best wishes for continued strengthening.
I am recovering from an illness and use some Tai Chi and Qigong to help regain muscle tone, stamina, improved circulation, and lung capacity. I use a portion of this video
https://m.youtube.com/watch?v=bcpelNJTDbY
as a warm up. Begin at 11:40 into the video and warm up through 23:29. This is a gentle warm up from neck to ankle that is good before doing any kind of routine.
If you sit and listen to the beginning up to 11:40 once, he gives insight to the benefits of the slow, calculated Tai chi movements.
After my warm up, I will do a routine with a variety of other videos, and I rotate them on different days so my body gets little stretches in new places to help make me stronger, and so I don’t get bored.
Here are two I have enjoyed especially those first days after convalescence:
Tai Chi
https://m.youtube.com/watch?v=XhNvdxbi-Jc&t=94s
Qigong
https://m.youtube.com/watch?v=1krhDR2f36A