Why would your trust in Mozilla have anything to do with using this browser?
Browsers based on Firefox are at the mercy of Mozilla. If Mozilla once again delivers a new function that is directed against privacy, those who develop Firefox-based browsers must either deactivate this function or also deliver it. And this is not always clearly documented. And Mozilla has simply acted against my interests too often - I no longer even trust LibreWolf.
(Leaving this aside, I also fail to see any advantage of Zen over Vivaldi.)