describe living as the opposite sex or gender as wrong for them, which is essentially a person with gender dysphoria's feelings about perceiving themselves as their natal sex.

Two problems with this take:

1. Assuming that "living as the opposite sex" is in any way related to what sex you are or feel as. I do not want to live as the opposite sex, I do not get validated by it, just the opposite. But I have to live that way, because I live in a patriarchal society. My lifetime living this way has unwillingly informed my (and everyone's) behaviour, but that does not make me more or less of a woman, it just explains my socialisation.

2. Plastic surgeries and artificially induced hormone imbalance =/= living as the opposite sex. The fact remains that changing a person's sex is impossible in any way. It is ultimately a superficial change.

I suspect that for a lot of people where gender dysphoria treatment doesn't work and especially makes things worse, they didn't really have gender dysphoria or anything like transsexualism to begin with

So, what did they have, then? What are these mental disorders where a person feels extreme discomfort with their sex and the way they're perceived, why are they not described as anything other than "trans" by the medical community and moreover why are we obliged to validate it as "real trans" with no ifs or buts or else we're fascists for questioning their identity?

which is essentially a person with gender dysphoria's feelings about perceiving themselves as their natal sex

You're assuming that not responding to current trans treatment = not being real trans. Given that changing one's sex is impossible, I don't really see how many plastic surgeries a person gets as more or less valid to one's gender feelings. However, you might argue in turn that the validity of the trans label doesn't matter, only whether transition will help with whatever mental disorder the person has, and since regretting these extreme body modifications is the only way to tell who is "really" trans, you've now got a bunch of people who underwent destructive plastic surgeries and regretted it after the fact, but they can at least comfort themselves in the knowledge that they're not "real trans". Here you see why GC are so opposed to such widespread availability of trans treatment: you're obliged to validate whatever the patient says, treat it like "real trans" because they want different pronouns and then if they regret it later after feeling like they've mutilated themselves, shrug your shoulders and say "Guess you weren't really trans", despite trans being the only current explanation for these conditions.