Klonopin is a benzodiazepine, and that is a highly addictive group which is often a total nightmare to come off, and indeed in those cases has first been a total nightmare to stay on (with ever-increasing doses needed due to tolerance). I would be very careful with using that, and avoid any doctor who plays down the risks. Personally I reserve benzodiazepines for short-term use only. Other addictive groups to be handled with caution include opioids and anti-epileptics. It's not well known that gabapentin can be horrendous to come off - I recently spent about six months recovering from gabapentin withdrawal, with most of the experience being after I'd completely stopped it (the doctor had tapered me off too fast, which didn't help). I was far worse off than I'd have been if I'd never tried it, and I still haven't bounced back to where I was before.
As for how severe ME is in various countries, or the relative prevalence, it would be insane to pretend that we can make even an educated guess. No one has a clue. It's a condition where there isn't even a reliable and commonly-used test for diagnosis, or even universal consensus on the diagnostic criteria, for heaven's sake. Misdiagnosis and lack of diagnosis quite possibly occur more often than accurate diagnosis. There's no cure. There's no universally effective treatment. Patients tend to end up off the radar in terms of medical and social care. It's not like, say, heart attacks, where there is a good record of who gets them because we know how to diagnose them, and because they end up requiring hospital admission or causing death (and even so, it's entirely possible that mild heart attacks are under-reported). We are simply not going to start getting even halfway reliable stats on this until there are a) universally agreed diagnosis criteria; b) a universally agreed and thoroughly accurate test which can be applied easily (as opposed to something so expensive that it's almost never used); c) ME patients are actually being treated properly within mainstream medicine. That's a long way off at the moment.
In terms of speculating about where ME might be worse, it would not be unreasonable to guess that there may be a correlation with the general state of health in a country. I would expect that poor diet or lack of access to healthcare would be exacerbating factors, yes, but such things can be surprising, and it's always very complicated as there are so many factors. I've noticed that patients with ME in America seem to be on far more meds than patients with ME in the UK, but I haven't yet been able to determine whether either approach causes an improvement. It's not as if there are swarms of people recovering in either country.
Meds - yes, of course they are risky and have side effects, no one is disputing that. Since medication intolerance is a common aspect of ME, and since most if not all people with ME find that most medication is unusable for them (due to side effects and/or lack of effectiveness), I think that most people with ME are on very little, if any medication, for the first few years, and sometimes long-term. I was mostly on no medication whatsoever for the first decade, with only very occasional use of meds every few years. It took a good doctor and an awful lot of experimenting to find anything that helped symptoms at all, and it's only a few symptoms. In one way this is good: it means that I'm less likely to be on a dangerously complicated cocktail of meds, and it makes it easier to monitor the meds for side-effects.
Psych meds for physical purposes - this is well known and has been for decades, as drugs have a multitude of uses. Two examples are valium (diazepam) as a muscle relaxant, and amitriptyline for pain or sleep (note that it's used for these purposes in a much lower dosage than it would be as an antidepressant). Similarly, some meds used for physical purposes can have notable effects on the mind.