(I absolutely agree - especially when it's google turning off features when you're using FF... it feels blatantly anticompetitive).
V8 on its own is a technological miracle.
But all funded by a firehose of crazy privacy invading ad revenue.
So. I'll live with the odd pause and a bit of battery drain. I gave Google 10 years of my life as an employee in exchange for $$, I'm not interested in giving them the rest of my life for free.
What if you could take the benefits of the spending and jettison the side-effects?
It's called Brave, they have their own ad blocker in the source code written in C, so it can't be hamstrung.
Perhaps you haven't heard of Chromium. If so, that may be because Chromium doesn't spend as much on marketing as Brave.
https://www.chromium.org/getting-involved/download-chromium/
I personally like that Firefox isn't based on webkit/blink.