While I understand where you are coming from, take in consideration that the beast didn't start at Assyria because the other four beasts didn't exist either, because they hadn't overrun Israel yet. The kings are not kingdoms because that would mean that only 3 had fallen at the time: Babylon, Medo/Persia, and Greece. It was with Babylon that God declared desolations on the Jews and Jerusalem. Assyria has nothing to do with it. Niether does Egypt because even in Daniel 11, when the man of sin is on the rampage, he fights the king of the South, which is in Egypt, meaning Egypt has no empire. Thought the Egyptians under Ptolemy did capture the Jews and treat them harshly, that was short lived. If considering this, that would make only four kingdoms having fallen instead of five, because Rome hadn't fallen yet.
Assyria is out of the question because they never took over Jerusalem, instead they were swallowed by the Babylonian Empire. Thanks and the Lord bless you.