Hawks have to trade Collins, right? He clearly isn't a good fit with Trae and the Hawks need to do something and moving Collins seems like their best bet. Not sure what they could get for him or what team makes the most sense (maybe Dallas), but that seems like something Atlanta needs to do.
How about this
Dallas - Collins
Atlanta - Markkanen, Boban, 26, Dal 24 1st (lotto)
Cleveland - Dinwiddie
Cleveland could then sign and trade Sexton somewhere and get different assets for him since they have Dinwiddie to fill that role. Dallas gets a solid 3rd player and the big man they are lacking. Atlanta gets a nice shooting big man (on a reasonable contract), a bruiser, and a couple of 1st's to help replenish the coffers or to use in a trade.