Flew into PMI last week - a single 'masks mandatory' announcement at the boarding gate, but no announcements while on board and absolutely no enforcement or even hinting by the crew. Most (80% ish) passengers not wearing a mask. Perhaps the de facto policy is now to inform passengers of the requirement and leave it at that. So if you want to avoid wearing a mask on board I don't think you'll have an issue, regardless of what the Spanish government decide (it's moot anyway as nobody in the terminal, health control staff included, wore one!)