I hope you're having an okay day,
@RedFox. From reading the thread it sounds as if you've really been having an awful time of it.
As for the tests ... I'm wondering who it's for?
Is it for doctors? If so, it's unlikely to help. They already know it's not a test for ME, and they're more likely to question what would motivate someone to put themselves through something that unpleasant than they are to look at the results. Many of us have seen concrete evidence of abnormalities in blood results waved away as "insignificant" by doctors, so they're unlikely to be swayed by something they view as far from concrete.
Is it for you? If so, will you be convinced by the results? They might be normal for your age and activity level, or be inconclusive; they might show a pattern suggesting PEM, but the trouble is that you also know it's not a validated test for PEM. The phenomenon probably isn't unique to ME anyway, and test results always depend on interpretation as much as anything. Will you question whether it was done properly, or interpreted properly? Will you keep wondering whether you ought to do it again, with a more knowledgeable doctor or different equipment or a more up-to-date protocol?
I wonder if it might help more to focus on finding better support for your struggle with such poor mental health. No-one has found anything that works for ME, but there are approaches that help some people manage their PTSD. Having to live with both that and ME must be exceptionally difficult, but one of those conditions has more treatment options than the other, is taken more seriously by medical professionals than the other, and might be where the potential for the greatest improvement in your quality of life lies.
I'm sorry if it sounds like a ridiculous suggestion because you've already hit numerous brick walls. I've no understanding of what it's like to live with PTSD, or to have to search for the right support at times when you may be least equipped to find it. I've been at the ME game for more than 45 years, though, so I know that one pretty well. And whatever the question, the answer rarely includes the words "doctor" or "test", at least once other conditions have been ruled out. It's a really shitty situation, but unfortunately that's where we are, and there's more potential for further harm than there is for good.
I wish I could help more. All we can do is be here if you need us, I guess?