I suggest adding a new payment method: pay with cryptocurrency

There are only advantages and no downsides to it:
- very low fees for the merchant (<1%)
- no chargebacks possible unlike CC or paypal
- no currency conversion risks, you only have to deal with euros

As payment processor I would use https://www.coinpayments.net/ because they support like 100 cryptocurrencies.
Then there is also the big player out there which is https://bitpay.com/ but they only support BTC and BCH.

There wont be alot of people using it at the moment, but it will increase over the years.

paying with crypto is a waste of money