Might look lopsided at first but it satisfies all parties.
Boston drops enough salary to get under the tax and only drops about 10~ places in the draft (depending on where the LAC and Boston finish) while getting a bench player who can contribute at times in Mann.
Brooklyn gets a late FRP in next years draft for taking on Simons and gets off of Mann 2 years early for taking on extra salary and swapping an early SRP for a late FRP