It's still in beta (under active development), so for fairly serious projects it's not yet viable in production in my opinion. But I'm using it for two personal sites, and it works perfectly. It's exactly the kind of tool I was looking for: open source, self-hosting, easy to install, easy to use and well maintained.

Baserow[0] is really good!

[0]: https://baserow.io/

Baserow is open-core, and some views and JSON-export are behind a subscription. Not a bad thing per-se but needs a mention.

Maybe NotePlan[0] can sync with iCloud?

[0]: https://noteplan.co/

Exactly the same for me! I've been using Firefox forever, and always will.