Hello there, Torleif67.

Yes, you can use the steps when recording customer payments by depositing the payment to Undeposited Funds and then create a Bank deposit transaction to add the bank charges. This way, you'll have the option to select the correct currency on the bank deposit page. By then, QuickBooks will automatically convert the amount in your invoice to the selected currency. For more details, you can use this reference for more details: Record and make bank deposits in QuickBooks Online.

If you have connected your bank account through online banking, you can use this article that will help you match and categorize bank downloaded transactions to avoid duplicate payments as well. 

Please let me know if you have other questions. Take care and have a great day!