Other than Things, the native Apple Notes app is great. It's simple, fast, and works with a fuss. Sync also seems reliable enough for me.
I don’t know but is it too much to expect an email client that runs exclusively on my device, doesn’t phone home or leaks metadata??
Disclaimer: I haven’t tried it but simply inferred this from their privacy page. I could be wrong.
2. OptiPerl (Check its screenshots https://www.uptiv.com/free/optiperl/ )