If you want to try something cheap, try the Amazfit BIP 6 watch. It costs around 1/4 of Apple watch, has most but not all of the same sensors (can't do ECG). It has far too many configuration options for my taste, but it does mean you can make it look like Apple like with Apple watch like battery life or configure it to last well over 3 weeks on a single charge. TL;DR: software is kinda clunky, but the hardware works well, and it's focus is on fitness.
I'll echo this, I've been buying these for my wife since the original Bip, and the battery life alone is more than worth it. She wears hers nearly daily.
