Celts have to play much better basketball. There is no magic bullet. We likely can't handle many off nights from Brown, Tatum, and Horford, and we can't have Rozier continuing to shoot <40%.
Jaylen and Jayson have to get their shots, and Horford can't become the Invisible bigMan.
Frankly, I think our odds are about 25% or so of beating them. Without Kyrie (and Hayward), they're the better team, unless maybe Embiid gets hurt again, then it's pretty even.