6 Angels who didn’t keep their first domain, but deserted their own dwelling place, he has kept in everlasting bonds under darkness for the judgment of the great day.
“Angels who didn’t keep their first domain” These angels were not the ones who fell with Lucifer in the beginning, before God created men on the face of the earth. They fell in the days of Noah [Genesis 6:1-4] according to 2 Peter 2:4-5 which says, “4 For if God didn’t spare angels when they sinned, but cast them down to Tartarus, and committed them to pits of darkness, to be reserved for judgment; 5 and didn’t spare the ancient world, but preserved Noah with seven others, a preacher of righteousness, when he brought a flood on the world of the ungodly”
The fallen angels in Jude 1:6/Genesis 6 were so bad that they received God’s judgment immediately. I believe that these angels are the ones who are mentioned in Revelation 9 as the Locusts. In the Book of Revelation, demons will be released from their prison in hell [abyss] to torment those who rejected Jesus and have the mark of the beast for 5 months.