> most of the bugs that Rust could have prevented right on the beggining are already covered (Chrome also uses fuzzers and static analysis tools to automate C++ code)

This isn't even close to true...

https://chromereleases.googleblog.com/2020/08/stable-channel...

Here's one from just this month.

Here's another from just this month with another fifteen issues: https://chromereleases.googleblog.com/2020/08/stable-channel...

There are hundreds a year like this. I could find many, many, many more.