Actually there is something that does that, my favorite watch: https://www.withings.com/us/en/steel-hr
The battery lasts a month. The only thing which would improve it would be NFC payments, but one can't have it all.
Also looks good IMO.
https://www.citizenwatch.com/us/en/product/BZ1005-51E.html
https://www.citizenwatch.com/us/en/product/BZ1000-54E.html
In theory, its capabilities included phone search/filter and visual/vibration alerts. Not quite a smartwatch, but at least some connection to the digital ecosystem.
I was excited when I heard about this, particularly the Eco-drive, as it meant no charging would ever be necessary. I have one non-Bluetooth Eco-drive which has been running continuously for 12 years without changing the battery.
In practice, the Proximity was a disaster. Owners reported dropped connections, late notifications, and a terrible iOS and Android app. The first two problems, from what I read, related to insufficient power. It wasn't enough to maintain a Bluetooth connection. The third issue is common to many companies that do not have mobile app engineering in their wheelhouse.
Citizen discontinued the models. They have a real smartwatch now (https://www.citizenwatch.com/us/en/product/MX0008-56X.html) but it is not Eco-drive.