Standard Notes is fantastic, assuming that:

• you don’t need to collaborate in real-time with your notes (you can share them after the fact and there is a way to give multiple accounts edit access to the same note, but it looked complicated and I haven’t explored it)
• you primarily use a keyboard - mobile counts, even if you’re using speech to text or Scribble on iPad - rather than wanting a canvas to draw on.
• you’re not trying to upload documents and annotate them

StandardNotes has the following going for it:

• it’s FOSS
• it’s easily self-hostable
• it’s also offered as SaaS, and if you use that your notes are e2ee
• if you self-host you can still use the official mobile apps (but those are open source, too)
• it has a web app, mobile apps, desktop apps on Windows, Mac, and Linux
• there is a variety of editor plugins created by the community that can be used even if you use the free SaaS offering - check out https://github.com/jonhadfield/awesome-standard-notes for a list.

I’ve been using StandardNotes for a few years at this point (as a paid user on their 5 year plan, which no longer exists as far as I know) and have also developed an editor plugin for it.