If you go down this difficult path why are you buying Mac in the beginning?
Besides, if you don’t trust Apple what makes you think that they won’t bypass these apps. They are using a bunch of apis provided by Apple to function.
I am not saying this argument directly. Apple has a big ads business. Still it’s not their CORE business. If you want extreme privacy but think that you can be anonymous just using little snitch, buy it cash etc. then you have a very big problem. If Apple really wants to track you, it can. That’s their OS, folks. If you don’t trust Apple and want extreme privacy, use Linux.