I think a strategy could be to play Brissett some minutes while having Tatum or even Holiday play at the 5 for some minutes. One knock on Kornet is the belief that Gafford/Lively might out-physical him and be more effective grabbing boards, but Brissett is a hustle guy who can also grab boards and Tatum is more than capable of playing the 5. And playing small might not be a bad thing for a Dallas team that's poor and a bit slow defensively largely due to Luka.
Or they could also just let Kornet/Tillman combine for maybe 6-10 minutes depending on rotations.
I think Tillman is playable in this series. Yeah we might compromise offense a little but he's a great defender and very capable on switches. For just 6-8 minutes, it's not bad especially if it's timed for when Doncic is out of the game.