A very good friend of mine has an M1 MBA with only 8GB RAM, and he says Safari is actually worse than Chrome for slowing the machine down when he has a lot of tabs open. A surprise to both of us, but there you go.
Regardless, if users have choice, they can make their own mind up. At the moment, it's webkit or nothing on the iPhone. On the desktop, Chromium dominates, not because the other browsers have to use it, but because they can, and because users like it, regardless of the anti-Google opinions here on MacRumors.