Stuck in "rest and digest" instead of "fight or flight"? Could this be part of dysautonomia? Dorso vagal shutdown?

Disclaimer: So I'm pretty sure I have POTS, though I'm not diagnosed yet, and there might be some other stuff going on as well, maybe Long Covid, maybe some other stuff that just happened to show up in the last few years. I also haven't completely understood yet, how exactly POTS relates to Dysautonomia, so sorry if this isn't the right place to ask this after all.

My most disabling problem right now is the constant fatigue and brainfog. It almost feels like my body isn't fully awake. It kinda feels like that kinda sleepiness you get when you just woke up or when you just ate and could take a nap now. But more intense, and instead of only lasting for a short time around those times, it sometimes lasts for the full first half of the day, other times I'm stuck in this 24/7 for weeks/months.

But recently some of my symptoms have been a little less again, sort of an anti-flare up, so that sometimes I do actually kinda manage to get out of this state, like I finally wake up. I'm suddenly not drowsy anymore, the brainfog isn't completely gone, but at least I can use the little brain capacity I have instead of spending it all on trying to fight through the tiredness. My muscles stop feeling weak, my body feels awake and stronger. Like, I wouldn't say "fight or flight" fully, there's no anxiety or restlessness or anything, but just... idk, awake and alert, the way you're supposed to be during the day.

I don't think it's just circadian ryhtm weirdness, because it's not that regular I think I do still have a circadian rythm on top of that, with some extra level of sleepiness and sometimes even some wakefulness, and that one is as regular as it's always been. But it feels like the rest of my body kinda doesn't follow it, or at least has an extreme inertia compared to it?

Now I've seen some people, especially on the Long Covid subreddit, but also on the POTS one, say that they feel like their nervous system is stuck in "figh or flight" mode. So it seems like that can be related to dysautonomia, so can the opposite also happen? Or is this probably something else? Is there anything that can be done about it? I also made a similar post elsewhere recently, and someone suggested dorso-vagal shutdown, which doesn't sound like it fits completely, but maybe it's part of it? Is this a thing? Is it related to dysautonomia?

(Background Info just for clarification: Overall my symtpoms have been going on for the past 3 years. I've been dealing with basically constant (though fluctuating) brainfog and (especially mental) fatigue (no PEM though, so no ME/CFS, if someone wated to suggest that) and oftentimes also some nausea, dizziness, more frequent headaches/migraines, and some other small stuff. My dizziness and pre-syncope symtomps have actually been pretty mild and rare, ever since I got my iron levels fixed, so I'm not sure if those things are connected to POTS, but I've heard they could all be caused by it, and they do usually get worse, whenever my more POTS-like symtpoms get worse.)