I’ve got this enabled - the only one that’s been more than a mild pain in the ass is the UTC timezone change. Always takes a minute to remember why a site is telling me my appointment is at 2:30 in the morning.
I tried setting:
privacy.resistFingerprinting.exemptedDomains to the domain
privacy.resistFingerprinting.testGranularityMask -> 4
I still get utc in slack