I have just discovered Unotes for Android: https://play.google.com/store/apps/details?id=com.evjava.android.unotes

I found it because I was looking for notes that support really good nested tagging, like how CintaNotes does it on Windows.

Unotes uses tags to organise notes into feeds, and when you select notes in a feed it can show a tag tree of all the other tags that are found inside the notes in the feed. It's

free and ad-free, so easy to check out if you're interested. Notes are stored locally and can be backed up to a local folder. No built-in sync.