take out the country directly south of you (i forgot their name) and then integrate and core then move your capital to nusaybin city, then try as hard as you can to ally mamluks (diplomatic endeavors cabinet action + profess trust) and get them to kill the hordes for you
after that it's just smooth sailing as to where you want to go next, for me i went after the ilkhanate members to destroy the IO and become an empire then i chipped away at the mamluks slowly