If your an opponent playing Boston in the playoffs, I think the strategy is to just leave Jrue + Horford open and force them to beat you from 3. They can probably still do it a few times but it's the best chance teams have. Memphis did it to Jrue a few weeks ago where he shot 4-17 from 3, and Horford was terrible against Indiana two nights ago from distance.
That's where the C's may need to adjust as well