You're positing ME as being triggered by the virus, a theory already put forward in relation to EBV infections.
If I'm understanding his post correctly, I think that the OP is considering the possibility that, rather than a trigger, ME is a virus, in long form.
Long-form COVID is accepted, almost without contest (or at least any that I've come across), as being a series of emergent conditions that are an extended form of COVID, not something endogenous simply triggered by COVID.
I didn’t find this to be a consensus in the articles about the theories behind long covid:
https://evidence.nihr.ac.uk/themedreview/living-with-covid19/
https://www.nytimes.com/2021/01/21/magazine/covid-aftereffects.html
https://www.frontiersin.org/articles/10.3389/fmed.2020.606824/full
I found that the virus still being active despite the negative tests showing otherwise is one theory among many others (mostly about a way too robust immune response, autoimmunity, abnormalities in the brain, etc), but the vast majority seems to treat long covid as a post-viral condition and not an ongoing infection, hence the alternative name: post-covid syndrome.
And since COVID can be asymptomatic, it could be possible that Robin Soderling was able to be " .... among the very best in the world ..." while still harboring a virus that would eventually overwhelm his immune system and present with symptoms and longer consequences.
Do we have any indication of asymptomatic Covid causing long covid? With all these people, contacts etc tested, this is something that might not go so undetected.
Yes, we can say it was started by coronavirus the same way we can say some past childhood trauma that was always there in the background actually caused it, it just needed a final trigger. Possible, but we have no real indication of either at all, whereas we actually have a very clear starting point with a well-documented event in these cases. I’m not against finding other risk factors, pre-existing genetic predictors etc, but I’m against totally negating the event that started the actual symptoms, saying it wasn’t actually the cause at all. So even if a coronavirus somehow contributes to this, I can only see it as a risk factor, not the sole cause for the above reasons. (And now I’m only talking about the cases triggered by other viruses of course.)
Sorry, I don’t want to sound harsh, I just really don’t see this scenario being too likely.