Linux on desktop, self-hosting and GrapheneOS too. I have a few smart watches, namely PineTime and Watchy by SQFMI but... honestly I don't wear them anymore simply because I try to be as minimalist as possible. In fact just yesterday afternoon I was wondering if I could do without GrapheneOS because I might actually NOT need a phone. So... what do you want out of watch? I can recommend both but honestly it depends on your need.