I need some advice from other parents about younger kids

The child in question is almost 6, just started kindergarten and amab.

TL;DR at the bottom since this got longer than I expected.

He has expressed interest occasionally in "traditionally"/stereotypical "girl stuff", but we never explicitly gendered stuff. Who cares if a boy plays with a pink toy? It's plastic. So that was whatever, but more recently, he's been talking about sparkly pink or whatever color different things like shoes or curtains. Seems a bit more like something, but still we never say "that's a girl thing" or "boys should like..." so it could just be what he likes.

He's talked about long hair before, but he doesn't like getting it cut, I think because the electric clippers were loud, and he is likely on the spectrum. So, sure, he wants long hair as a way to not have to do the haircut.

But here's the more serious part.

A few nights ago, he explicitly asked "are you gonna buy me a bunch of dresses when I get to be a girl?" we were a bit shocked to hear something so blatant, especially because what he was watching on TV was the big robot fight scene at the end of the movie 😅. We asked something to clarify, I forgot what exactly, and he said" when I get to be a girl, when I get long hair like yours"

I just self-realized I was trans not terribly long ago, and have not explicitly said anything about it to him, so I'm not sure he knows anything about the idea.

I've suggested to my partner before I realized that he had stuff that made me question him. She tried to brush it off as "he can like pink stuff, there's nothing wrong with that" which is valid. But after he said what he said I looked at her trying to hold back laughter looking at her trying to mouth "I told you!" and she was trying not to laugh and looked something like "Holy crap you might be right".

It was kind of a funny thing, but like, what now? I'm not sure how to talk to someone that young about something so serious(?). I don't want to force them into a box to have to unpack later in therapy, but I don't want them to get bullied now. They have enough awkwardness and differences going on already that concern me. Also, her family may be transphobic/homophobic, but it's hard to say since they may be masking it since my partner's cousin came out trans. But mine blatantly is transphobic, and some of them likely still homophobic too, though probably a little less so(?)

I want them to live their best most authentic life they can, safely. And not to have to spend their late 20s/30s unpacking shit like I have. I just don't know what to do.

TL;DR: kid might be telling me he's trans without knowing the ideas; i need advice on how to handle things properly.