Firefox do have a mechanism to limit the amount of data being leaked for fingerprinting, but it’s disabled by default: https://support.mozilla.org/en-US/kb/firefox-protection-agai...
1. prefers-color-scheme is completely broken, even in the dev tools. Mozilla refuses to fix this in any way, it is allegedly "by design" that you have to disable all RFP protection if you're a web dev and need to test the dark color scheme of your website.
2. Similarly, RFP always vends your timezone as UTC with no way to change.
See example bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1535189
My "fix" for this involves using a janky old version of an addon that attempts to muck with the CSS/JS to reproduce the effect.