I think you can live with Luka averaging 30-35 PPG in the whole series. What you can't live with though is allowing him to also make assists all over the floor to give the other guys open shots AND Kyrie averaging more than 25 PPG as well. Then it becomes way more difficult.
I think the strategy needs to be physical defense, but also neutralizing Kyrie and the other non-Doncic players. That goes hand in hand. If you make Luka think a lot and pressure him into thinking he has to put up 40+ each game to have a chance, that bodes well for us.
Frankly, I think LAC and MIN didn't do a good job of this, they basically let Luka dictate everything on offense and barely made adjustments. They also didn't attack Doncic on defense either, they allowed Kidd to hide him. OKC did a better job of this and they probably were the toughest series DAL has faced, even Kyrie admitted that after the series. Boston has way more individual defenders AND shooters on the team, it'll be even tougher.