Looking at your post history about a Neo Byzantine Empire in the 20th century, I had an idea while doing my own post war TL that you might be interested in.
Basically, the Communist faction wins in the Greek Civil War. When the Tito-Stalin split happens, communist Greece, Yugoslavia, Bulgaria and Albania form their own little Comintern. When the
Istanbul Pogroms happen in the 1950s, the Yugoslav bloc intervenes, creating a Thracian Republic with Istanbul (or Titograd as the case may be) as it's capital. Africa and the Middle East would be additional areas to expand by backing communist movements and regimes there.
So you'd get a communist Byzantine Empire with tanks.
Second idea I had: a Neo Crusader state in the 20th century. Greece flips to communism again, so the British are reluctant to give up the Dodecanese Islands and Cyprus to Greece. So they decide to create a Dominion consisting of Malta, the Dodecanese and Cyprus. To make the federation between Maltese and Greeks work, they decide to embrace the identity of the old Knights Hospitaller, which historically held both Malta and Rhodes. They'd eventually abandon the British Monarchy and make the
Grandmaster of the Knights as head of state. They intervene in the Arab-Isreali wars as a third faction, siding with the Maronite Christians in Lebanon.
So you get Crusaders with tanks.
For extra craziness, have both tank crusaders and tank byzantines existing in the same world as bitter enemies.