Earlier quoted context omitted.
No. You do realize that people have stuff to do and want their browser to be both 1) fast and 2) compatible with all websites? Firefox is slower than Chromium, and always will have some compatibility issues, because all websites are made with Chromium in mind. You can pretend all you want that "well ackshually standards exist and all website makers should use things from the standard", but it's not realistic, everyon…
Chromium is technically faster but in practice it doesn’t matter if you don’t have an adblocker. Adblocking significantly lowers render and JS load and lessens memory pressure. It varies site to site, but keep in mind that ads have to be fetched and then displayed. That’s not free. Firefox with uBlock origin is basically as fast as a web browser can get.
Move your ad blocking to a different layer. Like say, network level.