I hate to say it, but WearOS might be on life support. So no Apple or Samsung, obviously...Moto appears pretty much done with smartwatches....Huawei might be banned in the US...So not many people left making good WearOS watches, for starters. And no one with the cutting edge tech of Apple or Samsung, or even Fitbit really.
Fitbit might the only chance to save WearOS. Polar/Garmin have some serious hardware, but they are gaudy and beastly fitness devices. I'd consider springing for TAG, if they had all the bells and whistles of Apple or Samsung. Fossil has some nice watches out there but in terms of features they're always 1-2 generations behind.