You should look at Garmin. They have models with battery life measured in weeks, not hours like the Apple watch. My 3+ year old 645 still gets 6 days of battery life.
I bought an Instinct about a month ago and love it. I like the G-Shock aesthetic which I know isn't for everyone but it's everything I want in a watch. The battery life is amazing as you said. I charge it once a week and even regularly using GPS for fitness tracking it's usually at around 40% (it can be extended further by using a GPS mode that polls less frequently). The interface is responsive and straightforward (and button based instead of touch which I personally prefer). Like a G-Shock it's waterproof and appears to be near indestructible. I can't see myself wanting to replace it any time soon.
I'm another Instinct fan, absolutely love this watch. Its just the right balance of smart watch features while not compromising on being an actual watch. I think the only real weakness is the Garmin software itself but its still decent.
Sadly most smart watches seem to be heading the direction of just being a tiny phones with apps and crap that I'll never need and the segment of people who are just looking for a few concise features in something durable and stable will eventually have no options