Joplin syncs with Nextcloud - Orgzly does too. Agreed, Jtxboard does - via davx5.
I’m currently using obsidian synced via syncthing. I know it’s not Nextcloud, but it works well and has a nice interface and lots of plug-ins - even on Android. It might be able to sync - not bothered trying to yet - if anyone has, please comment.
Good luck with your search.
Who gives a fucking shit about x fucking twitter? - let’s hope it crashes along with reddit !
PS cross post all the good stuff onto lemmy first - then just let it burn and sink!