You should reach out to Whoop and request they sync their data with Apple Health. This isn't an Apple issue, this is a Whoop issue. The more users who request it, hopefully, the more they'll see the need.
Also, to counter one of your arguments above, Apple Health doesn't do a lot of analysis on third party data short of showing it in charts, so there is still value to using Whoops app for that aspect of it.
As an example, my scale is Whithings, my bed had a Beautyrest Sleeptracker both of these services consume and contribute to Apple Health.
