Its ironic that Orthodoxy and fascism never took off, but the window for fascism being a "legitimate" political ideology was fantisically short. As Putin's Russia proves, Orthodoxy and fascism fit hand-in-glove. There is even a term for it in Orthodoxy: symphonia. Orthodoxy is naturally nationalistic (though it is a condemned heresy to literally make every ethnic group a church, rather ever nation-state has a church. This is why Macedonians should be under Serbians, Ukrainians under Russians, etcetera.)
I think Orthodox Fascism's missed opportunity was with Greece. If Ataturk died in the crib of small pox or something, and the king of Greece avoided a monkey bit, after WW1 Greece could have controlled the Dardenelles and Constantinople. This probably makes them strong enough for Italy not to invade, and like Bulgaria, they could be pro-Axis but not really get involved. If you butterfly away Hitler's expansionism (i.e. France walks out of Munich agreement), Fascism in the Balkans can take off (as it was OTL).
Bulgaria, Romania, Yugoslavia, and Greece would all be fascistic Orthodox states. During the ATL Cold War, they would play the east and west against each other and likely remain fascistic, as without WW2 fascism does not get discredited.
Orthodoxy would be bigger than it is today and it would also be viewed as alien, sort of like Islam is in the west. I also think it would attract less western converts, as Orthodoxy is starting to make some inroads in this department today.