Some of the Garmin watches have built in GPS, limited smart watch features, and battery life of several days. I had an older vivo something or another that was perfect for this, light and cheap. It had a HR sensor I never much bothered with it, just used the GPS for hikes and bikes.

Importantly, the tracking works fine without a phone. I would go exercise without having to bring a heavy phone along.

The newer models are more expensive, but have built in routing it seems. Shrug.

I don't use my old one any more and I'd be glad to mail it to you if you want.