If someone can remove the bank from this equation, then there is almost a perfect way to trade with cryptocurrencies.
We must define what a "bank" is though.
Because there are also some financial services that require KYC to be used, that allow you to send/receive money instantly.
These services can be used to buy and sell BTC via Bisq or Robosats etc, but the problem is that if you constantly send $50 to people on (say Revolut or any other service), then the service will know that the person XY sends $50 to random people occasionally and they may ask. They may just ignore it, but you never know.