Just some speculation on my part: Long Covid's fatigue is at least in part caused by red blood cells losing their round shape. They don't hold on to oxygen effectively so you end up with less oxygen going to where it needs to go, muscles, extremities, all of it. (
https://pubmed.ncbi.nlm.nih.gov/33758711/ for instance)
...If blood is altered, maybe it alters more than just oxygen circulation...? Maybe them being all whacked out of shape affects blood glucose as well, considering there are many, many people post-covid who have had blood sugar issues?
Assuming our bone marrow will get back to producing normal cells eventually (which I really hope is the case), blood sugar control as well as the LC-fatigue could resolve, would be my guess... In which case it'd be a matter of handling it as you are now, and waiting it out.
Just thinking aloud though. I have just guesses to go on, alas. I'm just glad you've figured the regular-meal thing out, I don't think I would've thought of that myself!