Many people feel that the angel being described in Daniel 10 is Jesus in a Old Testament appearance. But in verse 13 He (Jesus) admits to being detained by an angel called the prince of Persia, who I believe is either Satan or one of his underlings. How can anything or anyone stop Jesus?
You’ve answered your own question. The angel being described in Daniel 10:5-7 couldn’t have been Jesus because if he was, the angel called the prince of Persia couldn’t have detained him for 21 days. Nor would Jesus have needed help from Michael to be freed (Daniel 10:13).
By the description Daniel gave, it’s obvious that from a human perspective this angel seemed to be a very powerful being, but the fact that he was no match for the “prince of Persia” shows he was “just” an angel.