Cryptocurrency as a payment method

We would like to accept crypto as a payment option but we do not want to use a bank or exchange we would like the crypto to be transferred to a wallet and keep it in its crypto state. (we can then transfer it later if we need to)

We also need the option to add a fee in % to accommodate for fluctuations, exchange rates (changeable like we need to) and should be connected to the blockchain network to know what the current exchange rate is.

More than one currency should be usable but to start the two biggest and oldest players should be a priority (Bitcoin and Ethereum).