Whats the best exchange for immediate withdrawal?

My client needs to pay me but since i don't have paypal in my country, we're going with crypto. Does exchanges allow immediate withdrawal after buying the crypto? For context the account will have to be created first, and client can do kyc but i need the payment on the same day preferably. I heard there's a cooling period or withdrawal hold in most exchanges. The client is in germany. We both have no experience with crypto.