Maybe you are right, but if you present yourself like a privacy-first browser, the paladin of the free internet, and then you end up taking money from Google, your position and credibility don't look great.

Why exactly? It is just as much a positive for Google paying some (to them) small money to avoid lawsuits as it is for firefox to be able to stay afloat.

Do you have any reference to issues where firefox lost credibility?