Move One:

Trade Anfernee Simons to the Lakers. A most favorable 2026 second-round pick swap between Celtics, Bucks, Pistons, and Magic to Jazz, then trade a 2031 least favorable second-round pick swap via Utah, and an unprotected 2032 second-round pick to the Nets, Utah sends Jusuf Nurkic to the Celtics and Kevin Love to the Nets. Lakers send out 2028 pick swap to Celtics, and send Rui Hachimura, Maxi Kleber, and a 2032 unprotected second round pick to Utah, as well as forfeit their top 4 protection to their 2027 first round pick that the Jazz have. (This makes a 27.6 million dollar trade exception, so the Celtics will be able to pursue names like Naz Reid and Myles Turner without matching salaries in the summer or now, but in the off season is more likely)

Signings:

From here you got to go after a facilitator for sure, whether it's Chirs Paul after he gets traded and waived from the Clippers or Tyus Jones after the same thing likely happens to him, but a facilitator in free agency I like is Spencer Dinwiddie so I'd sign him he can fill it up as well as play make.