It's hard not to read this and come to the conclusion that we're mostly dealing with something psychosomatic (and as a reminder, a psychosomatic condition does not mean you are 'crazy' - it means you are having <i>real</i> symptoms that are mentally induced).
If "up to 30% of Americans who get Covid-19" have long Covid, where are the professional athletes who have had to retire because of long Covid? I can't even think of one.