To this general principle you can add browsers and websites; what the browser giveth, the websites taketh away. You may think browsers are slow... they really aren't! There's a staggering, even arguably insane, amount of optimization in there. But then we write websites that are barely adequate, and load them up with ad scripts that aren't even barely adequate, and blame the browsers for being slow.
Write yourself an old-school 1998-style static website without a big pile of fancy features, give yourself solid .css and .js caching and use it judiciously, and the browsers can blast content to the screen blazingly fast, for all the work it is doing.
If you even could feed a 2024 web site to a 1998 browser, you'd probably be able to eat a meal while it was trying to render facebook.