In Flash season 4 episode 18 (Lose Yourself) Devoe attack star labs and take the powers of all bus metas. He even takes away the power of Killer Frost. He could easily take the power away from Barry as he was laying on the floor or he could absorb his power too. Same in the case for Cisco.
So why didnt Devoe takes Flash's power?
Is it because Devoe can only absorb the powers of the bus metas?