Absolutely agree. I'm mystified that so many people abandoned the consistently excellent Firefox for the debatably equal but run by Google Chrome.
Of course I moved to Safari after that when I realized I could gain like another 1.5-2hrs of battery life over even Chrome, and Firefox has largely replaced Chrome as the thing I use if I need something non-Safari, now.
I'm a Phoenix adopter as well, but never left for the almost 2 decades that have passed. I do it the opposite way, Firefox is my main, but the native browser is my goto if I need something non-Firefox.
I'd like to do it your way, but there's many Firefox-only usability features that losing simply ruins the web for me.