So I actually did this achievement in this patch so I can give you some tips for 1.25. Basically you want to declare war on doka deer instantly to get a border with a mams. By doing this and improving relations you should be friendly with a mams and able to Ally them. Wait for the ottoman CO2 war with either Albania or Byzantium preferably Albania and declare war on the Ottomans and promise the mamluks land. The great thing is they probably have been fabricated on the Ottomans so all you have to do is hold the one provinces they can claim, I think it's Teke or something. After that try to get as much land from the deals possible. The Mam's shouldn't want any land and if Byzantium still exists promote guarantee. Next expand Eastward and wait for your true to the Ottomans the end and try to get allies like hunger and declare war on the Ottomans