Google still has control over Chromium. Manifest v3 is a Chromium thing, not a Chrome thing. All forks of Chromium will get it and none of the browsers using Chromium as a base has moved to fork and maintain their own version of Chromium.
This means that Google effectively has a monopoly over all browsers that aren’t WebKit or Gecko based, which is a tiny portion of all browsers. Leading to Google deciding how people access the internet. It’s already worrying that Google is the internet for a lot of people, the fact that they can do more or less anything with Chromium means that they can do whatever they want with the web standard.
That should be a major concern for everyone. Chromium needs to be taken away from Google.