Aware that this violates Newton's First Law of not asking for medical advice on the internet, but I thought given the various jobs and expertise here there might be an outside chance that someone could point me to some better professional resources than Google.
During COVID I had what was clearly a COVID prompted single pneumothorax (collapsed lung). The standard medical advice is that there are three types of pneumothorax: puncture (e.g. from a bullet); disease-induced; and spontaneous. Once healed and after a rest period (~12 months) puncture pneumothorax is not a bar to diving, but spontaneous is a lifetime bar. Disease-induced, however, is a "depends on the disease" case (which I understand from the one useful doctor I've talked to is a function of whether the disease acts on existing weaknesses in the lung, or creates those weaknesses.
Because I had COVID in March 2020 and the NHS triage system was flawed at best, it went undiagnosed for 5 weeks.* The eventual diagnosis treated it as a spontaneous pneumothorax, while acknowledging that it was caused by COVID. Because COVID was new, there is no option or research on the "disease-induced" elements of it, and so it's still unclear (I've asked doctors who are mostly unhelpful) whether COVID pneumothorax is a diving bar or not.
Two questions. First, although I can do my own Googling, has anyone had or heard of information or experiences relating to this and diving? Long shot I know. Second, since the problems with pneumothorax and diving relate to oxygen equalisation, free diving is still theoretically in - does anyone have any knowledge of or links to free diving resources which explain the differences in pressure / physics between free and air-breathing diving?
Again, fully aware this is a long shot, but military diving quals tend to be more comprehensive in the theory education part, and if you don't ask etc.
* Which, given subsequent figures for COVID pneumothorax of a 66% mortality rate with 100% requiring ventilation, and I achieved a 0% mortality rate with 0% ventilation, I'm going to categorise as getting COVID "like a boss", albeit a somewhat weakened boss who had to pause for a couple of minutes after every third step up the stairs.