I agree that some good will can go a long way. It's also surprisingly easy to just not use pronouns at all.

I was friends with a couple of trans people on college, and I would always either directly address them as "you", or use their name where I would normally say "he/she". It's not a big deal, I just hate that there is a subroutine in the back of my brain shouting "Don't say the wrong word! Don't say the wrong word!". I think that's the cognitive load OP was talking about.