Thanks for bringing this up.
Whether Daniel was written in the 160s BC or earlier, it certainly has an odd structure. Some of the later chapters seem like re-writes of the same vision - and for what reason remains unclear.
But the notion that Daniel should keep silent about what he saw, heard or learned - I think you hit it on the head.
I won't repeat all the scholastic arguments for the later date for Daniel's authorship, but I would like to cite some, including one or two of my own.
The year of reign statements give many clues and especially the difficulties Daniel has with identifying who Herodotus. Both Greek authors identify the invading Persians frequently as Medes. Thucydides claims that the battle of Marathon where the citizen soldiers of Athens routed the Persians was a defeat of the Medes. This was 490 BC. The king of Persia was Darius.
If the author of Daniel was a witness to the defeat of Babylon, he would be aware of both Babylonian and Persian records ( e.g., Cyrus Cylinder). If the author was living during the time of Persian control of Judea, he would be aware of Persian monarchs because they controlled his life. But if the author or authors lived in a period when Greeks had long held control over Judea and in which Persian and Babylonian history was a distant memory save for Greek telling of it, ...Well, you've got yourself an apocalyptic book for the Bible - to eventually be placed among the Writings of the TaNaKh and not among the books of Law or the Prophets.
There are links in the Bible ( books, chapters and verses) which tie together an apocalyptic vision to which many groups of Christians (understatedly) have seized. These include Daniel, Revelations and Matthew Chapter 24.
Matthew 24:15 is the only NT citation of Daniel by name speaking of an abomination in the Temple and whether it was time to run for the hills. But Daniel, if written circa 165 BC, could be speaking of the introduction of Zeus and desecrating rites by the Antiochus IV government. Whether this is what the reference means in Matthew is to this, perhaps, or it could be in anticipation of something that would happen in later decades ( the War with Rome) or perhaps the continuing threat at Rome's deification of its rulers would imply. Incidents in Jerusalem stemming from this Roman behavior are included in the account of Josephus Flavius as events leading to the war he describes. I suspect that Matthew was written before 70 AD, so I am inclined to think that the Roman behavior similar to that of Antiochus IV is more likely than a prophecy or a latter inclusion.