Watch makers rarely use the term "waterproof": https://www.hodinkee.com/articles/why-no-watch-is-waterproof. For a time, the FTC banned this.

The Fenix 6 is also 10ATM water resistant. ISO says a dive watch must be rated to at least 10ATM, but honestly: if you're going diving, you can just take off your smartwatch, since you'll want a dive computer anyway.