No, because Apple doesn't allow 3rd party browsers on iOS platform anyway. They can just enable content blocking at any time.
Apple can’t just enable content blocking because that would potentially break apps that use webviews for non-browser type activities.
Beyond that, the browser engine may be an irrelevant implementation detail to the end user, but at the ecosystem-level, iOS's Safari lock-in has many harmful effects that are already well known and widely discussed.