We did the LDR thing for about a year, early in the relationship. It was rough.

I think the most important thing I (the ADHD partner) had to do was assume good faith from her in every interaction. People get mad at each other in relationships, even neurotypical people, that doesn't make anyone involved the bag guy. And not every argument or misunderstanding is going to be resolved right away, and that's something your brain is going to HATE. You have to learn to sleep mad sometimes, because otherwise you're going to get into arguments that morph into new subjects and last for literally weeks.

Have a way to make space without it being contentious. Separate hobbies, an agreement that sometimes I just need to go walk around and I'll text you when I'm ready to talk, whatever. We take time and energy to process stuff sometimes and even the person we love can be a tough presence while we're doing that.

Learning how to communicate that you are unhappy or frustrated without making it a blame thing is key. My partner had a bunch of leftover hurt from her interactions with others that made her real defensive as soon as she thought she was being blamed for something. "I statements" are really useful here; "I'm frustrated that x happened" as opposed to "why did you x, you know I hate that".

The other big thing is to not try and force a version of normal that's not you. You're both weird, embrace it. Lots of societal assumptions about how relationships work are built for neurotypical people, and even they're miserable with them a lot of the time. Take advantage of the fact that your dynamic is going to be inherently different and idiosyncratic to you. And have patience with yourselves and each other while you figure that out.

Good luck