Unless you also got PEM with your long COVID, then exercise makes it a lot worse. Bro science is dangerous.
Just because some people have conditions that prevent them from exercising it doesn't mean it isn't the healthy choice overall.
And a cursory look at the literature for PEM[1] will show you that the recommended path to recovery isn’t “avoid physical exertion at all costs”, but to do what you’re capable of and slowly ramp up the intensity, in which case small amounts of exercise could play a vital role.
[1] http://www.phsa.ca/health-info-site/Documents/post_covid-19_...