It would certainly be more convenient if they/them became a generic pronoun for everyone regardless of gender. But at the moment it’s not nessararily polite to use it that way in all circumstances. There are people that only use gendered pronouns to refer to themselves, to the exclusion of neutral pronouns like they/them. Generally if there’s any uncertainty about someone else’s preferred pronouns you can just ask. If you wanna skirt around it you can introduce yourself including your pronouns which will give others a safe opportunity to do the same. Messing up someones pronouns can be embarrassing but it’s not the same as dropping a slur. (Though it can still be very hurtful to those involved.)

I haven’t used these resources but here are a couple links I’ve seen floating around. (Someone else please speak up if there’s any issue with these sites!) https://translifeline.org/ https://transrescue.org/ Hope this helps someone.