Getting these borders (or any borders) in Eastern Europe is, IMO, not hard. Not only is Eastern Europe a diverse region that is hard to draw borders in, but the borders that do get drawn usually accord to the wishes of outside actors. But what outside actors have been left un-Balkanized? Western Europe looks like a shattered plate, it won't be hosting any grand conferences on the "Eastern Question" for some time. Only Russia and Byzantium seem to be safe from this.
So with that in mind, here are two scenarios:
1.
Russian intervention in the 1700s destroys the Ottoman Empire and creates a Greek state that claims control over the Balkans, but is forced to concede autonomy to local actors until it gives up on dreams of centralized Empire and assumes a corporate character. Faced with Ottoman attempts to regroup, Russia launches several campaigns into the Middle East, enabling the "Roman Federation" to reclaim large chunks of Asia so long as it grants Russia and Russia-affiliated individuals (enterprising Germans, for example) concessions like ports. The remnants of the Ottomans, disgraced beyond measure, flee to Armenia, and after some dynasty changes assumes the name of Timuria. Meanwhile, the Wahhabis fill the void of authority in the Levant and Arabia. Upon seizing Baghdad they declare a caliphate or something.
Meanwhile, Britain and France are freaking out at Russia's land grab but both fall flat in the alt- (and very early) Crimean War and war-fever-fueled revolution takes care of both of them. Except the revolutions are nasty civil wars, and in the vein of Central America complexes of cities with similar ideology and a hostility for the other complexes become the basis for new successor states. Germany is never forcibly broken down by Napoleon, so unification efforts are local and piecemeal. Same for Italy.
Prussia and Austria fight a war of attrition so bad they collapse EU4-style. Rebels broke your nation and all that.
Poland-Lithuania collapses in on itself, with the Lithuanians going their own way. Wolhynia, originally split from Ukraine to dilute Ukrainian nationalism, ends up absorbing enough Polish influence for the separation to stick.
2.
Song China industrializes, becoming a colonialist superpower. The horrifically inaccurate borders and weirdly named and weirdly shaped blocks of land, designed with no apparent regard to anything resembling OTL's historical trends, were in fact drawn up by bureaucrats in Kaifeng. Except the Chinese also faced competition from other industrialized Asian nations, with the result that borders became even weirder as everybody tried to cut out their slice. As decolonization neared, the emerging elites thought of antique-sounding names for their patches of land and they stuck.
Meanwhile, the Roman Federation essentially ends up as TTL's Meiji Japan. The shift of power from Turk to Greek plays out like the Boshin War, and all things considered is wrapped up satisfactorily after some initial difficulties. They then join in the imperialization of their continent, so as not to be considered laggards.