I'm curious how you view Angels? Serious question.
There are fallen angels, as described in the book of Job. Satan is a fallen angel, and the demons he rules are, too.
Some angels fell. Some did not. The ones who did not (like Michael and Gabriel, mentioned in the NT) continue in heaven loving and serving the Lord.
Thus the fallen angels have sinned. The others have not. They are servants of God and are not to be worshiped.
Which is a rather good example, come to think of it. The angels in heaven indeed are sinless. Yet we are not to worship them.
They are not described as omniscient, to my knowledge, so I assume they aren’t.