Can you show me data showing that Firefox with dark theme, does a first load on a website just as fast as Chrome or edge? Same data point for with video buffer in frame? Pretty sure its noticeably slower in both scenarios with a dark theme.

I would like to buy a hamburger. https://youtu.be/Z6oeAdemFZw

Even if it was perfect and everyone should use it. The issue is that you can not remove (uninstall) it, which you should be able to do, especially for a browser.