That's about it. There's no treatment, there's no medication, and if it were to get worse the only option is a lung transplant. I have to learn to breathe more deeply and my heart will wear out significantly faster due to the higher arterial pressure and faster pulse. I've got to be careful exercizing; 50% diffusion is considered the point where a light jog drives you into hypoxia. My o2 sensor says I drop down to the low 80s if I miss a breath at the wrong time. That's just going to be the new normal for the next 50 years, should I be so lucky.
Honestly the oxygen is the least inconvenient thing. Each breath gets me a bit more air than a normal person would get on top of Mt Ranier, but I've already pretty much adjusted to that. Low oxygen is hard to notice and adjusted for quickly, but nobody talks about the CO2. CO2 is being locked into my blood by the same scars/thickening that are keeping oxygen out. Many people can relate to extended altitude sickness (and how much it sucks) but very very few people my age have elevated CO2 like this. The closest you can get is sprinting until you're sucking air, and you can't catch your breath even if you take the biggest breath you can, until your ribs creak. I have been living in that moment for six months. I highly recommend against it. At the best times I'm anxious and forgetful; at the worst I'm just lying down for hours trying to breathe as quickly and deeply as possible with an intense sensation of being on the verge of passing out. It sucks, its cutting into my lifespan and it's very seriously affecting my quality of life.
Long hauler effects like this seem to be in the double digit percentages, which puts the number of people around a hundred times higher than the fatalities. Seriously, it's very not fucking worth it. Even if I recover partially -which is unlikely, at this point- or even if you "only" get a less physical impact like postviral syndrome, its going to severely fuck up years of your life, FAR worse than whatever quarantine is doing to you.