Look into Bangle.js, it’s what I have, it fits some, not all of your requirements.

It’s open source, both the hardware and the software so no lock ins whatsoever.

They advertise a 2 week battery, mine lasts closer to a month between charges.

You have to install any features you want (every feature is opt in, not opt out).

There’s no speaker, microphone, or keyboard though, so no calling or texting straight from the watch. It’s currently £77 before shipping.