Albanians and Bosnians were already in Europe when the Ottomans arrived and converted to Islam under their rule. Albanians in particular did rise high in Ottoman society, I think an Egyptian ruler was Albanian in origin

Nonetheless Albanians regularly helped western Europeans in anti Ottoman wars and fought the Ottomans for independence. Why would they do this if the Ottoman Caliph was their religious leader?

I generally have the same questions about Arabs, but the Ottomans were considerably weaker by the time of the Arab revolts.