. . . . is established as speaking a language which has no gender pronouns, and for which (for some reason) the in-universe English translation convention is to use the feminine as the default. . . . "See, this is what it feels like when the 'generic default' of a language excludes you,
Sorry, but no, that's bullshit. You're talking about a situation in which she is used as the default and there
is no way to identify someone(or ones) as unambiguously male by pronoun. This is very much
not the same situation at all. A proper example would have been something like the Buffy the Vampire Slayer RPG, which uses she pronouns as the default, but still uses he/him for unambiguously male subjects.
As for myself, I hardly notice. I only notice when someone points it out to me, either directly or via a disclaimer. In the latter case, why are you justifying your pronoun usage to me in the first place?
Just do it and shut up about it. I really, really don't give a fuck, and I'm certainly not going to hand out woke points. I also don't give a shit about English language conventions, as trying to hold a language in place is just . . . not how language works, so seeing them flip the script doesn't bother me in the least. As long as they don't virtue signal about it. Fuck pronoun usage disclaimers.
ETA: This does give me the slightly evil idea to find the person(or persons) who wrote the disclaimer, tell them to "here, have a cookie" and then link them to that horrid Cookie Clicker thing in the hopes that they'll lose hours, if not days, of their life to it. It's nonviolent, and it might keep them from writing something else stupid for a while.