I assume by homogeny you specifically mean cultural homogeny? The Habsburg monarchy is indeed infamous for the many diverse ethnicities and people it counted among its subjects. So much in fact, that as the idea of nation states as the pinnacle of human progress garnered traction in the 19th century, it was increasingly seen as an outdated remnant from previous centuries, an anachronism that was doomed to fail.

After the Austro-Hungarian compromise of 1867 one can say that its constitutive nations were the Germans and Hungarians; but the empire continued to rule over Czechs, Slovaks, Poles, Romanians, Ukrainians, Serbs, Croats, Slovenes and Italians. It was a state of nationalities, not a nation state. But how does it compare to the countries you mention?

Russia ruled over a gigantic empire stretching from Poland in the west to the Amur region at the shores of the Pacific ocean. Poland, the Baltic states, Finland, Ukraine, Belarus, Georgia, Armenia, Azerbaijan, Kazakhstan, Turkmenistan and more modern states were part of Russia in the late 19th century.

Germany and France conformed to the concept of the nation state far more, but even here, Germany had Polish, Danish, Czech and French minorities, while France ruled over Bretons, Catalans, Italians, and - before 1871 - Germans.

Culturally, it is nevertheless true that Germany and France were more homogenous than Austria-Hungary. With Russia, this depends on how you treat Ukrainians and Belarusians. In 1910, German- and Hungarian speaking citizens made up about 43 % of the Austro-Hungarian population. 44 % of Russian citizens spoke Russian in 1897, if you add Ukrainian and Belarusian, you end up with about 66 %.

While this does suggest that the empire of the Romanovs was more Russian or rather East Slavic than the Habsburg monarchy was German or Hungarian, it is telling that at the end of the first world war both states had ceased to exist, with states like Poland, Ukraine, or Finland declaring their independence while others like Romania or Serbia were enlarged.