If that were thew case we wouldn't be seeing reports like those below:

https://www.aims.gov.au/information-centre/news-and-stories/highest-coral-cover-central-northern-reef-36-years

Monitoring of the reef has only been going on for 36 years. That's not a lot of data on which to be creating a doom scenario. https://phys.org/news/2022-08-great-barrier-reef-fragile-coral.html