All four sections of chapters 7-12 have Daniel receiving a 'guide' to interpret his visions or explain the apocalyptic nature of the future: one of them appears to be an (angelic?) figure within his first vision (7.16), the angel Gabriel appears to him twice to explain a vision and then the future (8.15-16; 9.20-23), and finally an unidentified angel appears to explain 'a further version' (10.5,14).The combination, however, is well-suited to an author living in Babylonian exile.
Likewise, Aramaic had changed since the time of Imperial Aramaic. One last indication of the antiquity of Daniel is the style of the apocalyptic sections.
Apocalyptic writings changed heavily over the life of the genre, and we have examples of them from throughout the Intertestamental period.
'you are indeed wiser than Daniel; no secret is hidden from you; (Ezekiel 28:3)' Anyone who has read Daniel knows 'no secrets was hid from him' refers to only the one Daniel that we know of. This on its own is a weighty argument that tips the balance for me to anything else considered.
I don't understand how you can say Daniel's apocalyptic sections lack an angelic guide.
One of the first people to dispute the traditional dating of Daniel was Porphyry, a pagan philosopher whose arguments have been preseved by Jerome.
He argues that some of the prophecies in Daniel are so congruent to the time of Antiochus IV Epiphanes, the book must have been written during his time (175-164 BC).
The column headed "14C Age" provides a raw age before 1950 for each sample tested.
This represents the ideal date for the amount of 14C measured for the sample.
seem able to prophesy events close to the time of 167 BCE accurately, although not the relevant events that occurred shortly after this time, but its narrative around the chronology of the Exile seems flawed.