I can see a plugin that transcodes WP blocks into markdown then posts it to nostr.
I'm pretty sure that markdown what most nostr clients expect to see in long form posts.
I dropped my long post on https://blogstack.io/ this AM just to see how it works. It is a very basic blogging platform, my gut is built on WordPress.
I think it has potential but only if developed into something far more feature rich.
Discussion
There's a plugin someone is working on now, but I haven't really gotten it to work yet.
https://wordpress.org/plugins/nostrtium/
Also, a friend that's done some WordPress development dug this up, and may have something in the works based on this.