Joplin seems like a good SimpleNote alternative. And I'm really after the end-to-end encryption

Joplin supports E2EE.

I appreciate the suggestion. I checked it out at the same time as Standard Notes.

It seems to break the Simple + Plain criteria. For example on the main nav, pressing "+" prompts to either New Note or New To Do. And all the references to "notebooks". Too much for me.

That's fair.

The syncing is bit janky if you're careful. But having a self-hosted option is what attracted me.

I don't trust anyone with my data anymore.

Apparently you can self host Standard Notes --

From Standard Notes: Standard Notes is free and open-source software, which means self-hosting both ends (the app and server) is both totally possible and very easy." https://standardnotes.com/help/47/can-i-self-host-standard-n...

I just ignore the To Do feature, and have everything in one notebook. This makes it pretty similar to apple notes

Have you tried Standard Notes? Less stuff to ignore. Still not ideal but much cleaner.

And holler if you find something that is even better!