I struggled quite a lot with sending money from Europe to the US as US banks do not adhere to the SEPA circuit and using US banks' coordinates to send money was impossible to do for me. (My daughter lived one year in US some time ago and I used to send her some pocket money every month).
I believe the easiest way would still be to sign up for one of those pre-paid credit cards like Revolut (they are free). They have an IBAN number so you can put money on them from your bank account via SEPA money transfer for the exact amount you. want to donate and use that one on GoFundme
With some of them, you can even create a one-time usage credit card if you are not comfortable giving your credit card number on the internet. It will expire as soon as you use it once, so even if someone steals it in the process it is pointless.
Which type of cards are available to you depends on the country you are in, I guess.
Just a suggestion.