I would not have asked this question anywhere if the focus had been whether cisgender people encourage the usage of two gender stereotypes.

But you did ask it somewhere, and you asked it about trans people, who aren't in a position to change it, but are unfairly burdened by it.

Surely you see how skipping over it for cis people "because it's obvious" to talk about trans people instead, is putting the focus and blame on the wrong group, whether that is your intention or not. Trans people can't fix it, and trans people are the most punished by it. There is no conflict, just trans people trying to live safely in a society that makes that hard.

I think these prejudices are actively harmful to non-conforming people, since they may be perceived as socially inept or weird (consider young adults/school).

That is a little confusing, because the premise of your post was about gender conforming trans people. Here, you're talking about the impact on non gender confirming trans folk though.

The crucially important thing is that trans people are punished however they perform gender.

It’s not my intention to vilify or blame trans people, whom you rightfully defend. I crafted this question with my mind set on the following: “If I were trans, would I be supporting gender stereotypes and/or how to avoid it”.

Yeah, I know you aren't coming from a place of ill intent.

And I know you're coming at this from the lens of someone questioning themselves. But like so many of us, you're struggling with things, because of a lifetime of transphobic baggage that shapes how you even think about yourself.

Here's the thing, if you're gender diverse, you're gender diverse already. It doesn't become true when you accept it, and it doesn't stop being true when you try and push it deeper. If you're gender diverse, you aren't "supporting stereotypes". In fact, if you express your identity to people in any way, society will go out of its way to punish you for diverging from its expected stereotypes.

Not sure where you read me blaming trans people for their own mistreatment

You are doing that, but I include you in the list of people you're impacting. And it's also something that so so so many of us do. It's the result of growing up surrounded by transphobia. We will do anything to undermine ourselves and talk ourselves out of being trans or gender diverse. Even if you're not gender diverse, the framework we exist in makes it really hard to work that out, because you punish yourself for even considering it, for even asking the questions.

And that's what this is. This is you, struggling with internal conflicts as you look inwards to your own identity, trying to find reasons why you shouldn't go further down this path, why in fact, it's easier to just suck it up and go back to the way things were. It's why you skipped over the impact cis folk have on this environment, and instead focused on gender diverse folk, because you're dealing with a lifelong pressure that makes you want to bias the outcome of your self reflection so that you don't find divergence and difficulty.

My advice to you, is to stop worrying about what your self reflection might find, and what it might mean, until after you've followed that path. If you're gender diverse, you're gender diverse already, and the important part is giving yourself permission to accept that possibility, rather than trying to focus on building barriers to the exploration. If you do find out you're gender diverse, then you can find a way of navigating that on your own terms, in a way that brings you peace and happiness. But find that answer first :)