Why are the Bengals not clearing cap by restructuring deals?

[Nepa]

Buffalo Bills latest to create cap space by restructuring contracts, in this case the contracts of Josh Allen and Von Miller. They were 19 million over, but created $32 million in cap space, allowing them to address their needs in free agency (which include safety).

https://www.espn.com/nfl/story/_/id/35854402/josh-allen-von-miller-deals-restructured-bills-create-32m-cap-space