It's a very different type of lock in. Chrome is based on the open source Chromium anyone can adapt ( sand said competitors, like Microsoft, do), and the vast majority of what it does is based on open standards. If tomorrow Google does something stupid with Chrome, like cutting off adblockers, you can bet your ass there are going to be at least 2 forks within a week. When Adobe did something stupid with Flash, you had and have zero options.

Nobody else can maintain a browser anymore, which is why almost everyone else dropped their own engine.

When google announced the "Manifest v3" thing, which does impact ad blockers, people cried, but nothing happened.

Yes, the standards are theoretically open, but concretely nobody else can keep up, Google-the-server launches X and Google-the-client implements it, and than they propose standardizing it but move on anyway, and everybody else plays catchup.

It's not worse than closed source Flash, but it's huge lock in anyway.