I think the weakness in the roster is the lack of front court talent (PF/C). We have an excess of guard talent with Smart, White, Brogdon, and Brown (Brown plays guard primarily due to Tatum being our primary SF). We could trade Brown but that would only make sense to me if the result was a more balanced roster. If we could get an all-star or all-NBA level big for Brown, that would make sense and balance the roster. There are not that many options for that type of trade though.
We could also trade one of White, Smart, or Brogdon. Any of these are not going to get back an all-star big but we should be able to get a reasonable, starting level big for one of them.
Barring a miraculous comeback in this series, I think there are going to be changes. All the talk is that the players don't believe in Mazzulla. I don't know if this is true but it certainly seems possible and aligns with how they are playing. You can't let the inmates run the asylum but if the coach cannot command the respect of the players, that is a problem. But I don't think changing the coach alone is enough. Most of the good teams have a big as one of their top 2 players. 3 of the "final 4" have that; Jokic-Murray, LeBron-Davis, Butler-Adebayo.
If you look at the All-NBA voting, we are not going to get Giannis or Embiid or Jokc in a trade but Sabonis and Randle are 3rd team. Others getting all NBA votes are Markkanen, Siakam, J. Jackson, Davis, Adebayo, Lopez, and Porzingis. I think this is the pool of targets. Brown could certainly get us Sabonis or Randle. Maybe even Towns (who did not get any all-NBA votes due to injuries but his is all-NBA talent in my opinion). Smart or White plus something maybe gets us Siakam or Porzingis. I think this is the type of move we need to make.