One thing that did seem to help build the lungs up a bit, or at least make the very most of what capacity I had left, was finding some vids on you tube made my singers and singing coaches about the breathing exercises they do to get the very most out of their lungs. Several ways to fill the lungs without just trying to take big breaths in, which I couldn't without coughing, Several made them to help people with lungs that had been done in by covid, it might be worth your while having a nose around on you tube. Don't ask for names, I spent a lot of that winter like a bloody zombie so didn't know my arse from my elbow.October last year, I wake up after few hours as well. Some nights its like I'm having quick naps during the night. It never really got into my chest so my breathing seems fine, although when I took my kids swimming once things opened up fully. It did feel like my lungs would give out when swimming under water, seem alright now though.