This is not true.
The Austro-Hungarian Empire was more diverse, with German and Hungarian minority nobilities ruling large populations of Czechs, Slovaks, Ruthenians, Poles, Ukrainians, Romanians, Serbs, Croats, Slovenes, Bosnians, and Italians with a variety of religious and linguistic variations.
“The Austro-Hungarian Empire was more diverse, with German and Hungarian minority nobilities ruling large populations of Czechs, Slovaks, Ruthenians, Poles, Ukrainians, Romanians, Serbs, Croats, Slovenes, Bosnians, and Italians”
America has fAmilies representing all of them and dozens never included in the Austro-Hungarian Empire as well. From Africa alone America has folks from Nigeria, Egypt, Ghana, Ethiopia, South Africa, Kenya, Liberia, Somalia, Morocco, Cape Verde, Sierra Leone and Sudan (and a few others). America has citizens and immigrants from every nation in Asia, Every nation in the Middle East, every nation in Latin America and every nation in Europe, including both Russia and Ukraine.
The Austro-Hungarian Empire may have been ethnically rich from a European point of view but it was no America.