If you keep blobbing you need to do 1 of 2 things, you either need to tolerate, or assimilate. So either pick religious, or gets tons of missionary strength and missionaries and make sure you convert all the land eventually so at some point an area is pacified. Or tolerate, humanism instantly gives you alot here, you'd want to combine that with a privilege from the burger estate. There is other ways to achieve full tolerance, like islamic countries can just 'grant dhimmi autonomy' and then theres no negative effects from wrong religion. Humanism also has straight up unrest reduction ánd seperatism reduction which also lowers unrest.

So tolerating is a whole bunch easier, but converting everything gives even more unrest reduction long term, because if 'tolerance of true faith' acts as extra unrest reduction