Two seperate trades!!!
Trade Gafford to the Lakers for Knecht and a FRP. Also getting back Kleber who should honestly be a lifelong Maverick.
Klay to the Nets for Mann and 2 seconds. Nets agree to buyout or waive Klay and he signs with whoever he wants(probably the Lakers in a realistic scenario and for the vet min)
There is one more part to this rebuild. Trading Caleb Martin to anywhere that can take on the extra cap without giving anything or close to anything back. Mavs throw in a second round pick as well. This frees a spot up for the Mavs.
Part1- https://fanspo.com/nba/s/general/trades/giHIbcdHRMEgzR/mavericks-full-rebuild-part-1-trading-ad
Part2-https://fanspo.com/nba/s/general/trades/qOYYiZ05jGrff3/mavs-full-rebuild-part-2-trading-kyrie