So, I'm having a surprisingly successful run as Aragon - currently 5 February 1528:

• Iberian Wedding decided to fire in 1528, putting Castile under my control (who happened to get partial control of Burgundy when the Burgundian Inheritance fired earlier in the game), and I'm not quite sure what to do with them - was actually considering declaring on them when it happened.
• The Ottomans have been calling me into wars against the Empire fairly regularly - they keep nibbling at the Hungary region and up into Bohemia, but they haven't really bothered to beat up on the Mamluks.
• France is surprisingly weak, mostly because they didn't get a chance to eat Brittany or get Normandy back from England, and I tugged them into a few brutal wars with Castile-Portugal in the past.
• Trade-wise, I've been trying to snag all the centers of trade I can - hoping to do some quick wars in Italy to snag Genoa, Siena, etc. and upgrade them to level 2 centers.
• Converted to Protestant as soon as I could, and force-converted my PUs as well.

Thinking of going after the Mamluks and pushing into Egypt and/or the Levant, or fighting Morocco-Tunis to get more of the North African coastline and shore up control of the Safi and Tunis nodes (have to pull in Tunis as a secondary since they're also allied to the Ottomans). Is this the right move? And what should I be doing in order to prep for the inevitable backstabbing of the Ottomans long-term? Also, what other achievements should I aim for? Was considering Mare Nostrum as well, not sure what else to look into.

Allies: France, Ottomans

Vassals: Naples (PU), Castile (PU)

Rivals: Austria, Mamluks, England

Idea groups: Humanist 7, Trade 6, Defensive 2

Current map and diplomatic view: https://imgur.com/a/mwoySlv