What if the Spanish weren't able to get Luzon because the rulers there don't want to cede/give/sell to the Spanish their land in exchange for privileges offered by the Spanish as what happened in OTL due to the Muslim Bolkiahs and Bruneian Aristocracy gaining dominance in Luzon in conflict with the Pagan Peasantry which was due to the their inheriting the Lands of the Tondo Dynasty, what if the Tondo Dynasty survived and remained their dominance in Luzon, centralizing and strengthening their control in it and kept it Backwater, where would the Spanish establish their galleon trade if that was the case, since Sulu is unconquerable as well is it possible for them to get either Formosa or Cebu as their center of their Galleon trade.