I know of various mortgage brokers both in and outside Spain. You also have the option of contacting lenders directly, though it makes sense to talk to lenders who are geared up for foreign clients.
A sensible first step is gathering the information needed for pre-qualification, which all lenders / brokers will want to see. I have a form that helps you do that (link below). If you fill it in I’ll send you the resulting document for checking. Then you have a useful document you can share with brokers / lenders.
Let me know if you think this is helpful. I’m trying to work out what service people value. I’m not a mortgage broker nor do I want to be one, but I can help people organise themselves for making an application to one or more brokers / lenders, and introduce them to a mortgage lender geared up for foreign clients.