Hoping for open source watch OS some day, so many OEM / white label cheap smartwatch/fitness bands. Already exists for cheap cloud cameras. Could be the F91W of our time.

Also I'd gladly ditch USB C for a few programmable media buttons. Standardize on some sort of bogo pins and buy 20 adapters or split cables to keep the water proofing.

Pinetime is decent: https://pine64.org/devices/pinetime/

You're in luck! https://banglejs.com/