@rfmcdonald's Tripartite Alliance Earth has a bunch of League (of Nations mandate) Cities, which include Constantinople and Jerusalem, which would be the obvious post-Great War cities to occupy and split off in most timelines with that sort of Ottoman dissolution.Greece defeats Turkey in 1923 and gains the entire western Anatolian coast, while not being able to conquer Constantinople aka Istanbul.
Moving the Capital to Ankara would be considered a sign of weakness in this scenario, so it remains in the now detached city, nevermind it being rather unpractical.
Especially as much of what was left of Rhomania was the Despotate of Morea.Technically, one could consider Constantinople in the Byzantine Empire's last years as a example of that.
Maybe Xiamen with the two islands remaining part of the RoC ala Matsu and Kinmen could be a good shout-out, on that note?You might be able to do something weird with China, if the Republic somehow manages to hold on to a city on the mainland and considers it to be the capital to reinforce their claim to be the sole legitimate Chinese government.