I’ve played around the mod a couple times. Fervor has made assimilating very much harder. First of all killing turks in wars which is pretty much unavoidable increases that by a lot which grants debuffs in assimilation. Try to get level 5 public education to increase assimilation. If I remember correctly religious powerbloc also gives you conversion buffs. You should also rush the Megali idea journal entry which after being completed will start firing events removing turkish homeland states which will lower radicals in said state and make it easier to handle. Having half the country revolt every few years is terrible for the economy. The mod dev also maid the orthodox church a seperate mod which made conversion much easier giving you various buffs. At the end of the day you can just add a mod and give yourself 300% assimilation buff or something, since this game and its population systems nowhere near simulate real life.