To accommodate the new Gravy => PSP structure, we will add a new field to the wmf_contribution_extra table called backend_processor, capturing the backend processor that the payment was processed by.
Gravy sends us over a payment_service_definition_id property with each payment authorization response in the format of $processor-$paymentMethod e.g. adyen-card so we will use this field on the front-end to populate the queue message and save it in this new field in CiviCRM.
This was initially discussed here
This will likely form part of the work related to T372468: Finalizing Gravy fields in Civi