Whether or not the Google programmers use specific proprietary knowledge about the behavior of Chrome to optimize performance is different. If they do, that would be similar to the things that got Microsoft in trouble.
https://tech.co/news/google-slowed-youtube-firefox-edge-2019...
https://www.techspot.com/news/79672-google-accused-sabotagin...
https://www.zdnet.com/article/former-mozilla-exec-google-has...
Google knows that every time they release a Firefox bug, FF's user percentage goes down a tiny bit. Repeat over dozens of bugs, for years, and you have a strategy.
There's one blog post from another Mozillian that I can't find anywhere that came out within the last year with other examples, I think it was on HN.
You are looking for https://web.archive.org/web/20180728122724if_/https://twitte...
I use Brave + Ublock exclusively.
Brave and uBO share filter tech and we aim to make uBO unnecessary (this may require setting shields to aggressive). We do much more than any extension can do, and Google has made it clear they will further restrict extension APIs.
https://www.theregister.com/2019/05/29/google_webrequest_api...
https://brave.com/privacy-updates-7/ (latest in series)