Hello Jumel

If you hand over your house via a Dacion en Pago on account of all the debts you hold with the bank, you will be clean in terms of debt at the bank and won´t appear in any List or database of defaulters the bank may have. Other banks have no access to your transactions with that bank and won't know whether you processed a Dacion En Pago. In any case, they can check a defaulters list and if your name doesn’t appear there , they should not have any issues to grant you a loan.

You need to be sure that all the debts with your bank will be cancelled once the Dacion en Pago has been completed. That is, all the debts ( financial products, credit cards, etc ) and not only the one related to the mortgage.