Who owns most of those mining farms ? Do you know these people ? Or you just trust them because you hate banks ?
Also ... decentralization means lack of responsibility if something goes wrong ... If you wake up in the morning and your cryptowallet will be empty you can bite your ass ... you cant do nothing ...
I doubt my wallet would be empty, but if it was then it would tell me I didn't protect my self enough. Hiding behind Z address is not enough of safety, you need to do a lot more than that to be truly anonymous. Still Z address is a lot more of a privacy than a mere public address.
Of course everything is based on centralization, because currently you need some way of payment to get mining equipment. Mostly you have to pay with real money, because you don't have any coins yet. Later on you can use your coins to pay, so this is where decentralization comes in play, at least almost. While paying with crypto the receiver most likely converts it to fiat and makes sure the payment for the product is comparable with "real market price".
Bitcoin is not asic resistant, so most of the mining happens in China and Russia, so you could say it is controlled by a groups of people. But if these groups stopped mining, then the power would be back in the hands of private persons, or the ones who have mining equipment. Most of the cryptos are centralized in this way yes, but it is because the profitability of mining. If mining wasn't so profitable with huge investments in equipment, every minable coin would be more decentralized as mined coins would spread around the world more evenly.
I don't hate banks tbh. Money and banks work just fine to me. Cryptos are just a hobby and interesting thing to follow and read about.