The Romaioi had the same problems that the Empire in the West had, although Orthodoxy in the East as in the West served as a stabilizing factor, but as in the Latin West, the Orthodox East had problems maintaining any kind of stable source of manpower loyal to the State. Part of the problem was too much centralization and high taxes, debasing the coinage, but all of that is ancillary to the moral, and there are many accounts of the immorality of the Romaik Empire told even by Monks and Bishops, threatening of a deluge. Indeed, when the city fell in 1453, most of the troops manning the walls were Italian and German mercenaries.
I’m sorry but your analyses and comparison of Eastern and Western Empires is incorrect. The centralization and high taxes were not the root causes of the fall, they were the problems of the 200s century not the 300s.