Been there, done that, and barring a miracle medical breakthrough, the researchers and doctors appear to be years away from fully understanding, let alone treating, long covid fatigue and other issues. Toward that end, we're pretty much on our own finding "alternative" (medical and non-medical) options that may or may not work for each individual. I will tell you that red light therapy (RLT), also known as photobiomodulation is one of the few research-based therapies that has helped me with fatigue, provided I use it daily for 20 minutes. There are a lot of "things" marketed as RLT. Be very careful as only a handful have actually been independently evaluated in medical studies, and most are foreign knock-off goods with no proof of usefulness. Studies published in peer-reviewed journals will identify which RLT devices were used and how effective they were. I used one of the RLT panels at a local spa before purchasing one; yes, it is very effective, for me, and others I've recommended them to. I suggest looking at Platinum Therapy Lights, which have been used in some studies. Related to long covid, see: https://platinumtherapylights.com/blogs/news/red-light-therapy-for-inflammation Doctors are relatively clueless about alternative therapies, but always check with yours before engaging in them.