To clarify:
Meadows did not agree to a deal.
His testimony is coerced.
He had no choice.
If the DOJ gives him use immunity he has to testify truthfully because what he says cannot be used against him, so he cannot stand on the fifth.
However, anything he says to his compelled testimony cannot be used against him.
This doesn't mean he cannot be prosecuted. It means that anything he says to questions after being immunized cannot be used against him.
This means he hasn't made any deals.