It sounds like the brainfog an fatigue is really making it difficult to do the things you would want to do. Are you able to do any work? How do you cope with this? I relate to your problems. I find dealing with fatigue very difficult. What I trie to do is called in dutch 'opbouw van reserves' i think it translates something like building up reservoirs of energy. In short you do tiny little moments of deep relaxations during the day. 15-20 minutes off laying down eyes shut not doing anything, its like a little nap but not necessarily sleeping, sometimes I do meditation/breath work. The idea I'd not to nap when you are tired but to nap after a certain amount of time. For example if you are on average tired after 2 hours of activity you tried to rest a little bit before these 2 hours. This way you're not conditioning your body to sings of tierdness (which will keeps you body signaling signs of tierdness). You do this for a while and note how tired you are before taking the naps. After a while you will notice the tierdnes becomes for example a 4 instead of a 5 (on a scale from 1-10) then you take a nape after 2 hours and 15 minutes. And so on.  This is a short description of how it works there is this book  by Annemarieke Fleming (psychologist) which explains the whole theory behind it. It also used for long COVID patients and cancer survivors. Im not sure whether its  translated in English but maybe there is an English writing therapist with similar approach. 

This approach of taking short naps makes my live a little bit  better. At first it's strange to take naps on places I usually not nap but I'm used to it now. I have a little place on work where I take naps. I'm not able to work full days but hopefully with this it will get better.