Some translations set each line of poetry farther to the right than the rest of the text to make it easier to read. The ULB does this with the poetry that is quoted from the Old Testament in 4:18.
This passage uses the term "Gentiles" to refer to all ungodly people who are not Jews. It does not include Gentiles who have become Christians. "Sensuality, passion, drunkenness, drunken celebrations, having wild parties, and committing disgusting acts of idolatry" were actions that characterized or typified the ungodly Gentiles. (See: [[rc://en/tw/dict/bible/kt/godly]])
Peter uses these phrases to tell his readers what he wants them to do. They are like commands because he wants his readers to obey. But it is as if he is telling one person what he wants other people to do.