I've used clients like Highlighter and Habla for making long form notes for nostr, but I never enjoyed them, nor did they work well.

I was browsing through nostr just a few minutes ago and came across a conversation that was talking about this sort of thing and someone in the comments mentioned a client that I have never heard of before called https://untype.app/

It's great. I think this may be the best long form note making / posting client out there right now. Super clean interface and other great features. Check it out, there may be something better but this really impressed me. You can connect an OpenPort API key for the Ai features and even export your notes as PDF's if you want lol.