My Garmin Fenix 7 Solar happily crosses the 20-25d mark, depending on usage.

I have most features enabled though, using it as "just a watch" (which is what the tunable battery saver mode is, which I used a fee times in a bind) it turns 2d remaining into 1w+, so I would not be surprised if it would turn the 20-25d into 50-75d ballpark, possibly more.

Instinct Solar and Crossover Solar seem to give the above a run with much longer times, a friend is getting a Crossover this month because of that. Unfortunately if the claim is true he's not going to be able to report success for a looong time...

Having its own tiny OS with Monkey C, instead of a cutted down Android variant, is also a big help for long battery life.

Withings watches offer a similar battery life, it really depends on how much the watch vibrates when notifications are routed to the watch.

I love my Withings. Given what I've read about the Fossil application experience, I assume Withings is better in that regard too.

Withings watches don’t seem to have a GPS radio, though. The advertised “connected GPS” means GPS date pulled over Bluetooth from your smartphone, at which point it’s becomes unclear which role the watch is playing here in the first place.

This is the case for many "hybrid" smart watches including the parents Fossil Machine. I believe the true feature is the display of distance travelled on the watch reported by the phone and app.

They also work well when you want to tell the time, which is more than can be said for some smart watches.

The solar version can last indefinitely if you’re outdoors for a decent amount of time.

My Garmin Instinct 2X lasts 42 days.