Morey compromises on three 1st rounders (one of which is top 5 protected) and a "vanity" 4th 1st rounder that will flip to a 2nd rounder. Kings get a 1st and vanity 1st from ATL which they flip to Philly for Morey's ransom, plus two of their own future firsts (2024 is Top 5 protected as mentioned).
ATL upgrades its wing defense and effectiveness in Barnes, as targeted by GM Travis Schlenk in a recent interview. Barnes comes on declining deal with only a year left after this season, so very favorable from a cap management standpoint.
Kings give in to pressure from (awful) owner Vivek Ranadive to get swept in the 8th seed, and give up their future for Ben Simmons and whatever's left of Gallinari when he's healthy. Also unloads one of their dozen centers (Alex Len) to Philly.
FWIW - I don't like this trade for the Kings, but Vivek is desperate and an awful owner, so it's very possible they do it.