I love Proton, I use them for my business. Sure they are missing some things. The calendar is too basic, no widget. Drive does not have a Linux client and no rsync support or anything useful. And now there is no desktop app For Linux (it's not electron?). BUT, I love the webapp and they bring a steady stream of nice improvements, and what currently exists works very well. They are a company with the right values so I love paying them and look forward to what's coming.

Just use obsidian and the github repo addon so all your notes are not only backed up in a private repo but also with Git revision.

Edit: reading your requirements I’m sure above satisfy them except probably ‘programming notebook’, unless there’s an obsidian addon for that.

I self host Trilium: https://github.com/zadam/trilium

Obsidian with plugins!!!!

You can create some very powerful workflows with dataviewer, properties and templates.

Whatever note taking style you want really, automatically moving them to folders, etc.

I highly recommend using unique notes with tags to start with, you can reorganize it as you need.

I have #snippets for code snippets, #walkthrough, #todo. Theres plugins to automatically move these to folders if you want.

Notes can easily link or embed each other too, so going from bug -> bug -> project isn't an issue. And creating glossaries is super easy with dataviewer.

Bookmarks for glossary's and searching with tags a keywords makes it easy to find what you're looking for even if its in a pile. And properties let you mark things like "completed: false" for todo items.

The best part: All of your notes are markdown, so you can easily move them elsewhere if needed.

Can someone answer this point I'm confused about: Why can't a phone generate bokeh blur using the same technique that an ordinary camera does, ie. a large aperture / small f-stop? IOW why is ML or depth sensing needed at all?

Unaffiliated, I found migadu (https://www.migadu.com/en/index.html) to be extremely easy to set up and having a nice ui to work with. Gives you only the basics but that's all you need.

As they say, storage space is not an issue in the 21st century, so the only differentiator between plans is the only thing that matters: the number of outgoing emails. You can have as many domains, as many aliases and as many addresses as you want, that's not a technical problem so there's no reason it should be a financial distinction.