I finally decided to get a smart watch over the holidays as well but didn't want the extra features that an apple watch has, plus I wanted great battery life, so I went with the Garmin Instinct 2 Solar. I just charge the watch every couple of days for 30-60min.
2S version (40mm) for my 7" wrist, but if you are bigger then the 45mm will work fine.
I wear my watch to keep track of my cycling and running, "body battery", heart rate and sleep tracking although I don't really understand how sleep tracking works yet.
The tiny screen is good enough for the data that I really care for plus it vibrates for calls or notifications on my phone which is all I want.