No.

I personally try to avoid gendered language, but if I do use it, I tend to check their profile-bio :)

I know that for some people it's quite a struggle. Whether it is their focus, lazyness, energy levels, unwillingness during their toilet time or something else.

So, I'd say no. That's part of why I usually just go for they/them. Just like when you don't know someone's pronouns irl

Just be more careful with gendered language. Also, the trans flag was right there

Just stop giving a fuck, there's a metric shitton of crazies doing janny work, it's unpaid and very unsatisfying. If they ban you, it's either their instance's loss or nobody's. The account costs nothing because it's worth next to nothing. I don't even need the links that I myself post and the others' I can see even if they ban my account. This is a shitpile, it being in the fediverse doesn't make it less of a shitpile.

Its an honest mistake and I think if you appealed the ban you'd have a good case for it, however as you now know that's the trans flag you can be more mindful in future :)

Generally I wouldn't take that kind of thing too seriously from hexbears they love conflict and actively seek it out

That's a pretty reasonable misunderstanding, I don't speak for anyone but myself but generally as long as there's no malice involved I'm not upset by an accidental misgendering.

I'm on jerboa too and didn't even know there were specific pronouns on accounts, I just chucked mine in my bio.