layout.css.visited_links_enabled set to false; geo.enabled set to false; media.navigator.enabled set to false; media.peerconnection.enabled (WebRTC) set to false; network.http.sendRefererHeader set to 0; privacy.resistFingerprinting set to true; privacy.firstparty.isolate set to true; network.dns.disablePrefetch set to true; network.prefetch-next set to false; webgl.disabled set to true
Don't forget to also use something like uBlock Origin, Token Tracker Stipper, and Decentraleyes. Pass is all through a Pi-hole and VPN and you're pretty safe. Make sure your VPN does not expose your NAT'd IP with WebRTC. Both uBlock Origina and ScriptSafe can help with this, as FF will sometimes crap all over its about:config settings with updates.