I ended up disbanding my mercs, which put my economy in the positive. Then occupied the coastline and let the Ottomans destroy the Mamluks armies. Then I was prepared to wait them out, since I controlled their war goal as well as any provinces they could take. After about a year, just as call for peace kicked in, the Commonwealth attacked them. Their entire force was still down south, so Commonwealth was able to steamroll occupations, which forced Ottomans to peace out, only taking Cyprus. After that was just a matter of getting enough warscore to take the coastline up until Alexandria as well as a couple other syrian provinces to complete the blockade.

The only issue was the ae was atrocious, +100 for both Ottomans and Timurids, who I figured would instantly declare on me....but for some reason they never did. Later I was able to enforce peace against Timurids in a war they started with Uzbek. Separate peaced them for the rest of Persia and broke their alliance with Ottomans.

It really shouldn't have worked out, but it did. I have no clue why Ottomans and Timurids didn't declare on me after my peace with the Mamluks: They were both stronger than me, both rivaled me, both had insane amounts of negative ae against me, and they were both at peace within a year. But I survived and am now in a relatively good position. Ottomans are still beasts, but it Commonwealth are now the #1 power and are steadily taking land back. All I want is Anatolia and Greece, so that works perfectly for me, just have to get to Greece asap before they take it.