Man I wish Casio would make a cheap fitness band in one of their entry level watch bodies. A miband in the shape of a F91W with oled and 3 programmable buttons for $40 would be amazing.
https://www.casio.com/us/watches/casio/product.ABL-100WE-1A/
With a heart rate monitor it's considerably more expensive.
I tried garmin, apple watch, whoop, and a couple other heart rate trackers recently… they’re very very uncomfortable when coming from a Casio!