It's possible that they did intend to separate out those things at some point in development, but never actually got around to doing it.
The scale-creep of Elden Ring makes it so that the game is, in a lot of ways, weirdly less "polished" than other Fromsoft "Souls-Borne" titles when you consider the significantly increased development resources available to it.
I wouldn't even know how to begin to argue it's less polished than any souls game. Dark souls has its entire second half, dark souls 2 has the entire game that's incredibly unpolished and dark souls 3 never felt particularly cohesive anyway
Does anyone give you pronouns in the game? They just call you either you, tarnished or champion or whatever as far as I can recall. Saves on having alternate lines if nothing else.
Humans in this setting are said to be born of the Erdtree itself (at least for as long as Marika has been a god) and the lore implies that sex isn't even something any of the people in the Lands Between do for fun anymore
So within this setting, gender itself could be seen as a vestigial tail of sorts that cannot be fully shed by humanity because evolution has been halted which is just part of the larger themes of stagnation and imperial decline
Or I could be high and maybe it has nothing to do with the lore
The purpose is the game being about skillfully slaying monsters. You're not supposed to create a character representing "yourself", you're supposed to hit stuff, hard. The story is barely something you can call a story. You're going to put a kettle on your head and hit stuff with an anchor. They simply didn't care about representation or even character customization very much, just about the gameplay and visual diversity of the world around you.
We're talking about Elden Ring, not Sekiro here. If Michael Zaki didn't want you to be able to represent yourself, or what you value in the game, he would've just given you John Eldenring to play as, and told you to go fuck yourself if you didn't like it.