You should definitely check out the pinetime. I’m about to pick one up myself. For ~30 bucks why not.
Default OS is a community project. I followed development for a few years. It’s pretty solid last I checked with good battery life and support for user apps written in rust
Just a note to any US hackers on here considering the PineTime, you'll need to pay $25 shipping thanks to our glorious leaders.
Second that. Have had one for 2 years and it's brilliant. Haven't yet tried to build any app for it. But it runs a month for me on single charge. I use it for travel or when out for day trips with family.
Does it have WiFi?
From the webpage https://pine64.org/devices/pinetime/
Does not look like it. Appears to be Bluetooth 5 and Bluetooth LE only.