Challenges guessing email addresses in Spain - particularly addresses for large Spanish financial institutions

Maybe a slightly niche question here but I am an SDR prospecting Spain at the moment and facing difficulties finding correct email addresses. Zoominfo + hunter etc seem to be pretty weak in the region, and the issue seems to stem from Spanish people often having multiple middle names, with their first name sometimes not being their formal name + other cultural idiosyncrasies. My company's target accounts are all financial institutions, with a preference for larger ones, so it's even more frustrating when combined with the multiple email formats a lot of these bigger enterprises support. To give a flavor of the accounts we're struggling with; Santander, iberCaja & CaixaBank. Therefore if anyone has any tips to share for these accounts or on prospecting Spain / southern Europe generally, I would be eternally grateful. Tips could be knowledge of good events that are Spain-based or well attended by Spanish financial institutions, or any tools/data providers that are strong in the region or, even better, verified email formats for those specific accounts.