Full disclosure: I did not have Covid. However, I have asthma and bronchiectasis and had deeply seated, long time mycobacteria and pseudomonas lung infections that weren't diagnosed until June 2018, by which time I had diminished from an "energizer bunny" to a "couch potato" - I couldn't walk a block without pausing. Then I started 19 months of antibiotic therapy - using up to 4 antibiotics at the same time - needless to say, unpleasant although one infection resolved and the other improved, but the meds were killing me. Those were stopped in December 2019, and it took until April 2021 to feel like I was back to normal.
My takeaway - lung damage can heal, or lungs can learn to compensate, but it takes a VERY long time. And pushing may not work, so you need to listen closely to your body.

You can find a lot of help here: https://connect.mayoclinic.org/blog/post-covid-recovery/ Some of the videos there speak about using a very slow rate in exercise increase to be more successful. That is, throw out the old "10% increase every 10% days" mantra
Sue