Ok yes I know this might be an overreaction to the Celtics' struggles but it's just an idea.

Sacramento Kings: The Kings try to buy-in and make the postseason for the first time in who knows how long (sorry Kings fans). They end the Fox-Haliburton 2 Pg experiment, because I think Fox has seen enough of Sacramento and needs a change of scenery. Jaylen Brown could be the best possible return for Fox, one of the best 2-way players in the league at this point, Brown could spread his wings and become the 'guy' on this Kings team with a solid supporting cast around him. They give up good draft capital and high-potential players in Bagley and Mitchell for Grant; but making the postseason maybe worth it for a starving franchise. They also get Pritchard to be a backup in the trade for Brown who should be very serviceable.

Detroit Pistons: Honestly, I don't fully know what the Pistons except in terms of a return for Grant. I feel the Killian Hayes experiment is about to come to an end in Detroit, and Davion Mitchell who could very well play next to Cade may be a great replacement. Bagley is one of the biggest wildcards in the NBA, but if there's one place where he'll get time and development, it'll be Detroit. And obviously, they get very good draft capital in the form of 2 FRPs and a SRP.

Boston Celtics: There's a huge issue in Boston right now, and honestly, there's a lot behind it. There seems to be an underlying locker room issue, but also things with playmaking, pace, etc. De'Aaron Fox helps solve a lot of those issues, and gives them a plug-and-play PG along with Smart and Tatum. Yes, Brown is one of the best young players in the league, but so is Fox (aside from the bad phase currently, we shouldn't read too much into it). They also get some great rotational players and some future draft capital through this. Boston have been searching for a good playmaking PG for a long time, and getting Fox is top-end for the dream; though giving up JB.

Celtics:

PG: Fox / Schroeder

SG: Smart / Richardson

SF: Tatum / Nesmith

PF: Williams / Horford

C: Williams / Kanter

Sacramento Kings:

PG: Haliburton / Pritchard

SG: Brown / Hield

SF: Barnes / Harkless

PF: Grant / Metu

C: Holmes / Thompson

Detroit Pistons:

PG: Mitchell / Jackson

SG: Cunningham / Hayes

SF: Bey / Jackson

PF: Olynyk / Lyles

C: Stewart / Bagley

Let me know your thoughts!