I get a new fingerprint id everytime I refresh the page (firefox, linux) -- so that might be sampling a tiny bit too much. audio and canvas fingerprint are constant though so it's probably plenty enough...

I think it might be because the performance fingerprints need to be bucketed. If they're too specific you'll never get the same fingerprint twice.

The same applies to macOS. Safari produces a unique fingerprint ID every time, and Firefox also has a different fingerprint ID with every visit.

If the fingerprint ID is unique every time, there is zero possibility of using it for identification.