Obsidian + Sync (for $8/mo)
If you don't want to pay, use git sync. Personally I think it's decent, have to deal a lot with merge conflicts (I have 3 devices), and using git on iOS is cumbersome.
Or, you can use the LiveSync add-on (need to setup your own CouchDB instance for it).
LiveSync is pretty good, real time sync is nice, but I rarely had a conflict since switching to it.