I think people are sleeping on Indiana a bit. I still view NY and PHI as the bigger threats in the East, but for PHI especially a lot comes down to health (if PG13 and/or Embiid are out, then no chance) and Indiana did play us the toughest out of the teams we faced in last year's postseason. Their defense is still bad but they have the kind of offense to give us trouble and potentially outscore us here or there.
That said, I also think it's a good sign that despite all that, BOS still went on a ferocious run late and forced OT on the road in a game they had no business of being in late.