That's 36 hours of normal use, with a 60 minute workout[1]. My Fenix 6 lasts 8 days of normal use and currently tells me it can record a 14 hour run even with only 42% battery.
My Apple Watch with Cellular enabled is the only electronic doo-dad that I carry on my bike rides, even up to 100 miles. At the end of the night when it goes on the charger, I might have 20% left. That's good enough for me considering I seldom, if ever, leave the house with a phone.
And if one could ever get a cellular enabled watch without an iPhone, I'll be first in line.
[1] - Details in footnote #1 on https://www.apple.com/apple-watch-ultra/