I know it will get downvoted to oblivion but the OP asked so whatever. I only use a simple txt or html text/notes editor sometimes (on both mobile and desktop). Other than that I use paper or don’t make notes at all. When I need to back them up or access them on another device, I just use a USB cable because Bluetooth doesn’t work on my machine for some reason
I can do better than that by using *.csv files on a desktop machine, and I’m squeamish about taking them mobile. so I don’t have to deal with sync’ing them.