devooops Can confirm.
I currently use manually harden Firefox, this means there are no unsolicited requests and I tested with an mitm proxy, enabling ssl decryption. Used to use waterfox then realised it was just as crap as brave.
Librewolf comes pre-hardend, but you need to delete the url in browser.safebrowsing.provider.mozilla.updateURL as by default that is enabled and seems to be the only unsolicited requests and "spying".
Also if anyone here uses brave for "Privacy" do a test with mitm proxy and disable ssl decryption. Your results will be that you find brave has more telemetry and data collection that vanilla Firefox?