If this isn't a targetted advert in my browser, I don't know what is.
And here's where you turn it off:
as someone else suggested, a fork is the best way to go. if you are most concerned about privacy, Liberwolf is the way to go. if you want privacy, but aren't willing to go as far as Librewolf does, then Waterfox is a solid alternative that provides better privacy than Firefox.