"Abstract and timeless thought operations with symbols that must correspond to God's intention, which we have difficulty reconstructing, exclude, in my opinion, the possibility of learning the language of angels*. The book of Daniel will remain sealed without God's help.
*In my opinion, for example, John the Baptist (in modern terms one would say: he had a genius ability) interpreted the Scriptures in exactly this way. How else would he have thought of "washing" people with water? That the Law is a shadow of things to come... he got the symbolism of the Law exactly right."
John the Baptist didn't have "genius ability". He had holy spirit.
Luke 1:39-45, 80 "So Mary set out in those days and traveled with haste into the mountainous country, to a city of Judah, and she entered the home of Zech·a·riʹah and greeted Elizabeth. Well, as Elizabeth heard the greeting of Mary, the infant in her womb leaped, and Elizabeth was filled with holy spirit and loudly cried out: “Blessed are you among women, and blessed is the fruitage of your womb! So how is it that this privilege is mine, to have the mother of my Lord come to me? For look! as the sound of your greeting reached my ears, the infant in my womb leaped for joy. Happy too is she who believed, for there will be a complete fulfillment of those things spoken to her from Jehovah.”...And the young child grew up and became strong in spirit, and he continued in the desert until the day he showed himself openly to Israel."
Luke 3:2-6 "God’s declaration came to John the son of Zech·a·riʹah in the wilderness. So he went into all the country around the Jordan, preaching baptism in symbol of repentance for forgiveness of sins, just as it is written in the book of the words of Isaiah the prophet: “A voice of one crying out in the wilderness: ‘Prepare the way of Jehovah! Make his roads straight. Every valley must be filled up, and every mountain and hill leveled; the crooked ways must become straight, and the rough ways smooth; and all flesh will see the salvation of God.’”"
It was God who gave John the message by means of holy spirit, that's why his message and actions "got the symbolism of the Law exactly right."
Jehovah hasn't changed. He can use His holy spirit today to help people understand the meaning of the Bible, including the meaning of Daniel's prophecies. You don't need to know "the language of angels" to understand who is the king of the north or the king of the south. You need to know Jehovah, through Jesus. He is the one who said...
"When the helper comes that I will send you from the Father, the spirit of the truth, which comes from the Father, that one will bear witness about me; and you, in turn, are to bear witness..."
John 15:26,27