I don't see the Mavs as being that bad defensively.
Dwight Powell does a good job on defense. JaVale McGee as well. So a solid 1-2 punch at center. The four main starters Kyrie, Tim Hardaway, Luka Doncic and Christian Wood are all middle of the pack defenders. Reggie Bullock is a good defender off the bench. Ntilinka a high level defender. Maxi Kleber is below average but adequate. Bertans is lousy. Josh Green good.
Dallas should be able to build a respectable team defense out of that.