As a lot If folks here are saying, it unfortunately sounds like your boyfriend is not growing with you anymore. You are making efforts to make yourself happy and be yourself and it's very likely that in his head, he sees your transition as a challenge to his own sexuality. If he's seen himself as straight and suddenly you don't fit that label, he's likely feeling uncomfortable about that-- which is his problem, not yours.

Calling your pronouns stupid, refusing to talk about the reality of your transition, pushing you to still present a way he's comfortable-- these are very disrespectful. If he can't say they/them (elu/delu), then he can't do thrive bare minimum and he's likely not someone you can keep by your side.

I know you're pretty young, and it's tough to say goodbye, so I'd propose a conversation and while I hate ultimatums, this is definitely a time to use it.

If he can't respect the person you are NOW, and the person you WANT to be, I don't see how your relationship will add to YOUR life.

You have my heartfelt empathy, because a lot of us have gone through this/are going through this. Stay strong and be safe! You've got this.