Theres another person here with that issue but I can’t remember her handle. I would put “sniff” in the search bar

I have a friend who uses a portable oxygen concentrator to increase oxygen. It uses the air in the room, removes hydrogen, and provides concentrated oxygen to breathe.

She has a different reason for using it, and right now is only using it while on an elliptical exercise machine. Not sure if Medicare will pay for it, but it’s probably less expensive for them to pay for. Her husband is a retired general surgeon and would not have her using it if it didn’t work.
https://my.clevelandclinic.org/health/treatments/25183-oxygen-concentrators

I really recommend you join the facebook page for people with paralyzed diaphragms. Fortunately I don't need supplemental oxygen with my left paralyzed diaphragm, but many of the people in that group do. They would share their tips on how they cope with breathing and dealing with Medicare and the insurance companies to get the oxygen supplies they desperately need. Most doctors don't know much about this rare condition, and I've learned so much about it and gotten amazing support from people there. Best wishes!