I don’t have CFS, but I do have a bunch of autoimmune issues that took years to properly diagnose. I can definitely emphasise when you say fuck the medical system. I didn’t get onto some decent immunotherapies (plasma exchange) until about 5 years after I first had symptoms, and by then I had a lot of progression and irreversible damage.

My main advice would be to consider your doctors as disposable (switch to someone else if your current one isn’t working out, assuming that you’re able to do this), keep level headed as possible during appointments, and make sure you explain how your symptoms are affecting your day-to-day life (i.e it’s not just a minor inconvenience for you, it actually hampers you from doing X, Y, Z).

Finally (and I know this is verging on class-reductionism) remember that most doctors don’t really care about you and are mostly concerned about their side consulting gigs or practice fees, so if you think they’re kind of doing the bare-minimum to just get you out the door, then push them to do more in the most diplomatic way as you can.