How so? First of all, think outside the box: you can earn and spend Bitcoin directly, without touching a bank. That was actually its main idea.
Furthermore: you can definitely buy and sell Bitcoin peer-to-peer - again: how it was intended. Peer-to-peer electronic cash.

I personally recommend Bisq as a platform to facilitate securely buying and selling Bitcoin (even through banks) peer-to-peer. As far as the bank is concerned, you just bought or sold something from / to someone.
They won't refuse a regular sized transaction from a regular other random person. The funds will not come from a centralized exchange's bank account.