Wow, that is a very long comment :)

So, I don't claim to be a neurology or brain structure expert, I just know what I know, and I haven't read the details on recently discovered brain structure differences. I will leave that discussion for another time.

I don't think there's any point arguing different types of sex characteristics of mutable vs immutable or visible vs invisible, or even expectations. We are what we are, and we classify people according to how we match what sex characteristics we have with what we expect. In lieu of a better system (read: more rigidly, but still logically defined), this is the best we have.

Your last part I find a little concerning though. What you describe as "making others comfortable" is essentially internalized transphobia.

There is no moral justification for undertaking actions just to make someone else comfortable at our own expense. If there was a tangible, probabilistic reasoning in play it might make sense, but there isn't - it's simply "they say it makes them uncomfortable, so I won't do it". I mean, dogs make me uncomfortable (got bitten once as a kid), but I wouldn't dream of telling dog owners they can't get on the same bus as me.

Having said that, if it's a process you're willing to undertake, then to be fair I applaud you, and certainly won't tell you you can't do it. But at the same time, it's not fair to tell trans women they have to restrict and potentially demean themselves just because "some cis women are uncomfortable".