I tend to prefer "file centered" apps, there's some cool one you'd use with Syncthing?
My favourite is KeePassDX; I would love a notes app with a 'material you' UI.
Not an easy step to find a text editor I like. I've tested pretty much all the ones I can find, the most decent UI is probably Orgzly but I had sync issues in the past, and it's just a decent UI.
Not sure if this will help you stick with orgzly, but it synced very well with Nextcloud. Must admit Nextcloud was easy, so didn't need to manually sync it any other way.