After leaving Simplenote I could never really find a successor. Kept jumping from one app to another - UpNote (very electron), FS Notes (very unstable; come across a bug every other day that it's tiring), then Bear (might move to it, maybe), Joplin (no sadly) etc and what not. Now I just try to use something that lets me keep notes in a folder and use it but then iOS becomes a mess unless I use iCloud. I could never find another simple note taking app. I wish Automattic took privacy seriously and kept the development of Simplenote afresh and maybe charged for it.
Maybe I am not supposed to find that one note taking app for me. Maybe it doesn't exist. That makes sense. I think it's about notes and not the note apps? Keep the notes and apps are a-changin'.