If you dislike both Apple and Google, then I wonder, with your skills, why you didn't consider using and improving PineTime with a GNU/Linux phone (Pinephone or Librem 5).
I have it on my radar since v1.0, and whenever I see the two older Android Wear devices in my drawer I keep thinking that I should put them to some new use (i.e. make them control home devices directly or similar).
Now that Gadgetbridge supports AsteroidOS, I would like to give it a try again but my device require a battery change and it's been hard to find one. That brings the major issue with AsteroidOS - very limited compatibility for newer devices.