Anyone voting for the Ottoman Empire as the least legitimate successor to the Roman Empire while raising states built off the bones of the WRE as being perfectly valid candidates or states whose only claims are a blood relationship to a past Emperor are on something or have a severe case of the Byzantiboo going on
The Ottomans maintained a more coherent transition of the Roman state apparatus and geopolitical niche than any other listed successor. They had the blood relationship to a past Roman dynasty, don't claim legitimacy from the same Germanic kingships that first toppled the WRE, and viewed themselves as a successor to Rome, the third religious iteration if you will. The House of Osman(since people seem to have a hard time distinguishing that they're not equivalent to their Turkish subjects or to the original Turks from Central Asia) ran a religious state with nationality/language being a distant second priority. Between the janissaries and the converts, they ran a state that was utterly dependent on the Greeks to function, that operated out of Rumelia. There is no more direct transition possible short of Mehmed II converting to Christianity.
The Ottomans maintained a more coherent transition of the Roman state apparatus and geopolitical niche than any other listed successor. They had the blood relationship to a past Roman dynasty, don't claim legitimacy from the same Germanic kingships that first toppled the WRE, and viewed themselves as a successor to Rome, the third religious iteration if you will. The House of Osman(since people seem to have a hard time distinguishing that they're not equivalent to their Turkish subjects or to the original Turks from Central Asia) ran a religious state with nationality/language being a distant second priority. Between the janissaries and the converts, they ran a state that was utterly dependent on the Greeks to function, that operated out of Rumelia. There is no more direct transition possible short of Mehmed II converting to Christianity.