> Antitrust doesn't really enter the picture.

I don't think this is true. Google Meet, Youtube, etc all perform worse on non-Chrome/Chromium based browsers.

I do think that the world's most popular browser, being owned by the same entity that owns Youtube, actively working to block adblockers (adblockers which, do *not* harm Chrome but do harm Youtube) is something for regulatory bodies to take into consideration.