You claim to stop spam, but what about the page-spam you initiate after an update??

[ErzeFranz0]

I do NOT need a new webpage advertising FF's latest "features" (that mostly aren't so great). To me, that's SPAM. I barely glance at it, and am mostly annoyed that it has appeared on my screen without me navigating to it. I'd put up a picture, but I think that's even more spammy, so I won't.

[Agentvirtuel]

Hello

Firefox policies https://mozilla.github.io/policy-templates/
Try OverrideFirstRunPage https://mozilla.github.io/policy-templates/#overridefirstrunpage

https://forums.mozfr.org/viewtopic.php?p=941315#p941315