While on laptop/desktop nothing beats txt (or md or org), it's just so uncomfortable using a text file like that on the phone and relying on dropbox or something.
And I get it, all the note taking apps on the phone have issues: not local first, proprietary, subscriptions, or no encryption, or a thousand features before making sure the full text search works even offline.
Last year I finally sat down and wrote my own PWA out of frustration [1]. There was a SHOW HN too [2]. Yes, shameless plug. There are only a handful of other people using it (and probably never more than that) but I really wrote it for myself and it's been such a relief the past year knowing I always have my notes whenever wherever and works exactly the way I want.
I probably spent <5h fixing a few issues in the past year. As far as I'm concerned, my problem is solved once and for all.