I'm with you on the second paragraph.
> But people wanting me to call them with another pronoun where I can no longer use biological cues is just cementing gender roles
I believe there's more to this. IIUC, for some (most?) trans people, there's actually something, probably related to their biology, that makes them feel as the gender they were not assigned at birth. They have may look like one gender, but feel like the other one: gender dysphoria [1].
These people might be fighting more for solving this issue than for getting rid of the gender roles. Some would actually transition to the other sex for this, though I would expect trans people to also be more familiar (and sensitive?) to these gender identity questions, since they had to think about them.
Would gender dysphoria be less of an issue in a society that would not have such gender-assigned roles? Open question for me.
Now, it would be best if a trans people could directly speak about this, because this stuff is mostly theoretical for me, I haven't experienced it first-hand.
[1] https://en.wikipedia.org/wiki/Gender_dysphoria