Most scholars assume that with the rise of nationalism and the liberation of the nations of the Balkans, the collective term "Romans", which was used since the Byzantine times to define the adherents of the Patriarchate of Constantinople regardless of their ethnolinguistic background, vanished with the emergence of national nomenclature. However, below you will read an interesting passage I found on "Understanding the Pre-Nationalist Balkans: The “Romaic” Community" by Raymond Detrez.
Sir Harry Luke wrote in 1936!
Orthodox peasants, not only in Greece, but even at times in
Serbia and Bulgaria speak of themselves as “Romans”… The
word “Roman” thus included not only the Greeks of Hellas,
the islands, the capital city, and the various Greek centers
of Asia Minor, but also the Serbs, the Rumanians and the
Bulgarians of the Balkan Peninsula and the Arab-speaking
Orthodox communities of Syria, Palestine, and Egypt.*
*Quoted by Kemal Karpat, An Inquiry into the Social Foundations of
Nationalism in the Ottoman State: From Social Estates to Classes, from Millets to
Nations, Princeton University: Center of International Studies, 1973, quoted in
Vermeulen, “Greek Cultural Dominance”, p. 228.