Hey! Saw this and I've been meaning to getting around to posting because I've been living with constant fatigue since Long Covid.
I've found that if I'm able to do some exercise I paradoxically feel less fatigued and feel more energised. That being said, it's taken me a long time to find a happy medium between doing too much and not doing enough. That's been the key thing for me really. Plus, I've found getting up earlier but then napping in the day also lessens my fatigue level - sleeping straight through for hours makes me feel worse weirdly.
Vitamin D and/or B12 supplements can also help. Personally, I haven't found that the Vitamin D has helped at all but I have been recommended B12. Everyone's different though.
Hope you've been feeling some improvement.