It’s not an Apple fanboy but imo it’s a lot more transparent on their side. There’s a switch for each and every service to use iCloud or not in the settings. Services don’t just re-enable their usage of iCloud after some random update and most importantly, they don’t just re-install apps you previously deleted. Or bloatware.
Now I get your point. Technically, I think it could be possible to only include the changes in Chrome. It would make sense for Google to push the changes all the way down to Chromium, though, as this would eliminate ad blockers on many competing browsers as well. Judging based on the past I would say this is what’s gonna happen