Personally this has been the most feature rich/open source one I could find, and it's what I ended up going for, there's an opensource app store, direct integration with gadgetbridge, a decent always on display much like the amazfit bip S, which also means a long battery life.

https://banglejs.com/

Casio with inbuilt calculator

If you can find a Pebble, they still work perfectly and the manufacturer doesn't even exist anymore!

anything that's compatible with Gadgetbridge should be okay. it keeps everything on your phone and doesn't even request a network permission, so the device can't phone home.

incidentally, I've got the Mi Band 7 (connected via Gadgetbridge] and I quite like it.

Pebble is peak smartwatch. Fight me on it, I wont change my mind. Its just smart enough, without being too smart. Battery lasts for days, its waterproof, and side buttons instead if some impossible to use tiny-ass touchscreen. Perfection.

I've also used a pinetime running infinitime for the past year, and I agree that it's not exactly feature rich. I like it though.

I've heard that 'bangle.js' is an open source watch as well, with a decent feature set.

I'm in the same boat. The buttons on my Pebble Time Steel are going, and I don't know what I'm going to replace it with.

the Pinetime watch, but it died after 6 months.

Oof, that's a shame. That was on my list of possibilities.

Been pretty happy with my Garmin Instinct. It has a cloud connection of course but seems pretty decent privacy wise.

I would say amazefit is the better option, check the compatibility with gardggetbride before buying.

I bought an Amazefit bip 3 years ago and am using Master for Amazefit, sadly the developer stopped updating the app. The watch/band supports only step counter, heart rate measure, sleep tracking. So, whatever options the app provides work fine for me.

I need to look for other app options when I upgrade.

I'm waiting for the next batch of Watchy's so i can't say if it is any good, but I have high hopes. They have a handy spec comparison chart between Watchy, Pine time, Bangle.js, and the beloved Pebble.

Pinetime by pine64

What happens wit a Garmin watch if you uninstall the app? Mine still processes notifications/etc.

Don’t know how close this gets to what you want, but I really dig my Withings steel. Small watch, standard analog face with step tracking subdial and a tiny lcd display that you can set to show different stats from the watch. You need an app to set it up, since it only has a single button for input, but after that I think you can just uninstall the app and be fine for the alarms you set up, heart rate readout, and whatever custom step goal you set. Also it lasts a month on a charge, which is absolutely awesome if you hate charging these damned things as much as I do

I got two Xiaomi bands, I think it was band 4, but neither work after like two years

Also sleep tracking sucks with gadget bridge, it was better with notify, so at that point it's crap hardware with closed software

I've mad a MiBand 6 for a while now - seems solid and you could, in theory grab all the data from it and process it yourself (via the Notify app). I don't know exactly how bolted down it is privacy-wise though.