The number of downvotes is bullshit, so you get an upvote from me. People tend to exhibit tribalism when it comes to browsers and distros; don’t ask me why.
I am a Firefox fanboy and long-time user, and I agree with OP that shit like Google and Amazon needs to not be in Firefox. But alas, these kinds of partnerships (esp with Google) are Mozilla’s primary source of funding, so I take it as a necessary evil.
Every browser and company that makes the browser is guilty of some horse fuckery (with Brave for example, their BAT shit). You have to just adjust the browser settings to your liking and get on with life, not dwelling on its flaws.
So just configure Firefox, make sure to install uBlock, read the Arkenfox GitHub page and harden Firefox accordingly, and enjoy using a pretty awesome browser. Do not use a fork (eg Librewolf) because they lag behind Firefox for security updates, with the exception of Mullvad, which is ok to use.
Happy browsing and welcome to the Firefox community!