I tried random Android watches. They all sucked.
I bought a Garmin Instinct 2 Solar. I love it. Charge it when I shower and that gets me by, have never had to charge it overnight. Battery is at 15 days currently.
I bought the same watch 10 days ago. It had 82% when I opened the box, I didn’t even charge it, and it has 39% now. During that time I had one 3/4 hour GPS activity, and 24/7 heart rate monitor + mobile notifications. I was also playing with it quite a bit to set everything up. Sunlight exposure was pretty low, so … I’m impressed.
It does everything I want from watch. Great readability in every condition, good GPS, reliable heart rate, long battery life (I keep forgetting to charge even my phone).