I would have a hard time believing Garmin hasn't been working on its own version of Whoop's offering (the software, not the hardware). Looks like Fitbit is following Whoop's lead and going with a subscription model:
https://www.theverge.com/2021/8/23/22638452/fitbit-charge-5-leak-features-premium-fitness-tracker
Given the price of the Fenix line, I really hope Garmin doesn't follow suit