Interesting theory but I wouldn't be so sure. I've been through healing journeys where the websites suggested all sorts of deficiencies and supplements, but in the end I came to believe I just needed to slow down.

We know that COVID depletes NAD+ reserves and NAD+ is the main electron transport molecule in the body (second one is FAD+ in some cells in the brain). So if you suddenly run out of electron transporter, it would inhibit most of your systems, making you tired all the time, and the systems that are already operating near their maximal capacity will start failing. This might kick off a chain reaction that is later transformed into condition we call long covid. It would also explain why it is different for each person as everyone has different organs in bad shape and why people with certain organ damage have similar symptoms.

I can speak from experience having gone through a healing journey where the online sites promoted a single supplement as the cure.

I later felt that this focus on this 'replace lost nutrients' approach, while it might have had some merit in the acute phase, also kept some people in denial of the factors which led them to their health crises.

Any nutrient you take will be downregulated by one of these thousands of processes shown here: https://external-preview.redd.it/Yepk20IXyppuST6erisGCPg716V...