Using fancy apps, where you can do formatting, place links, etc? I spend too much time futzing with all that stuff and less time actually getting stuff done.
What I do now is have markdown files, and use the OS folder system for organising. I then use OneDrive for syncing - this works perfectly fine between MacOS and Windows, and for both I use Visual Studio Code for editing. For android I use an app called FolderSync to sync and TMarkor for editing.
Has been working perfectly for over a year now.
Only asking since this was also the editor I ended up settling on in Android, but it seems like TMarkor is just a repackaging of Markor without any references to its forked(?) source.
My requirement was that the editor had to be open source so that I could audit the repo and compile the APK from source, as well as potentially fork it for personal modifications if needed.