Currently, it is unknown how much in fees is being paid when using SumUp. SumUp does return it in their transaction object, which is checked at least once while validating the webhook input (https://developer.sumup.com/api/transactions/get#transactions-get-heading). That way, it should be able to save it in the purchase object. Minor refactoring of the backend code handling this might be needed.
Currently, it is unknown how much in fees is being paid when using SumUp. SumUp does return it in their transaction object, which is checked at least once while validating the webhook input (https://developer.sumup.com/api/transactions/get#transactions-get-heading). That way, it should be able to save it in the purchase object. Minor refactoring of the backend code handling this might be needed.