The desire to build a self-defense kit from Google and the Internet as it is today

(if you don't want to go through all my strident words) Thus, after this rant, my question is: where do I start from to build my surviving kit and my right to be private and disclose personal information to who and when I want to. How I become the actual owner of my device?

(I'm Italian, sorry for my Englishi) I feel I'm enduring too many aspects of my everyday life. Because of my scarce knowledge on many things I am enforced to accept other's companies decisione. My approach toward The mega companies who, in my view, are owning Internet is obsolete and definitely ineffective: I don't use X, FB, instagram, TIK TOK and I boycott Amazon. I just use YT, via freetube, reVanced and Newpipe, until this will be possible. (but, alas, I pay to use chatgpt 4, rather useful tool sometimes) I don't own a sufficient knowledge to use the net ad the mobile phone to riaffirm my independence and anonimity in this once beautiful world of collective enthusiasts and clever people that once was internet.
Also I find infuriating that I'm spied constantly for the simple fact of using a device that I bought with my money and that from the has never be mine but Google's. I am just sick of it, but I, repeat, don't have the knowledge to switch and turn into a citizen who strolls in the world of internet without being followed by 'people' who wants to sell you constantly something and wants to profile you. I find this too aggressive and unbearable. Thus, after this rant, my question is: where do I start from to build my surviving kit and my right to be private and disclose personal information to who and when I want to? **** How the f**k I defend myself from these greedy psycopaths (in the film 'Don't look up: Peter Isherwell, the billionaire CEO of BASH Cellular, was a pricelees portrait of people I cannot stand and for humanity are more harmful thant covid-19)