Apparently, I read today, Chromium will eventually get proper first-party domain isolation and proper fingerprinting resistance as the default behavior of the browser, not even as a patch series forks can apply, but in the original browser as the default behavior. They are calling the initiative Privacy Sandbox, and they are implementing many new APIs to keep advertisers happy, with the goal to remove all the privacy invasive means of tracking and fingerprinting advertisers use today. I would say the privacy is good in Chromium based web browsers as soon as they lock all state such as cookies and cache to first-party domain, and remove the common fingerprinting vectors. So maybe Vanadium will get all this for free in the future, and there would no longer be a need to run another browser.
However, they have expressively said they will not try to prevent tracking of country, and thus also not timezone. That does not leak enough information to uniquely track a user, and advertisers want to know what country the user is in. So they likely will not go all the way like the Tor Browser patch series have done.