My guess to why Cipollone came clean, assuming he did.

[Novara]

12. Maybe

But it doesn't mean that he won't toss everyone else under the bus to save his own ass. He cautioned against doing illegal things. Whether or not they listened to him IS EVERYTHING. So in that, he is very valuable to the J6 committee and possibly the DOJ.

He WANTED the subpoena. He wanted to testify but he wanted to be forced to do it, to protect his ass. His motivation was probably to save his own ass at the expense of others.

He's an interesting character n this drama. He may have only been advising against certain actions because it was his job. But if those he advised went against his advice and took illegal action anyway, their criminality is even more egregious. And he has the receipts. He's the one person who can say, "Yes, he knew it was illegal and he went ahead and did it," with complete authority.

Cippolone didn't "turn." He's saving his ass by telling the committee that yeah, he warned these motherfuckers against doing exactly what they did. They knew it was illegal. As far as I can tell he did his job. At least on 1/6. I can't speak for the rest of his tenure.