This is totally wrong. The 10 speed is a completely different transmission co-developed by Ford and GM. It shares nothing in common with the 6 speed.
My opinion, for drivability and creature comforts, the LT would be the better choice. The Custom Trail Boss is really a work truck interior which is fine if you don’t mind the spartan, completely drab look. I think the LT interior is much nicer with better contrasting finishes and materials, and much better equipped. LTs have a bigger infotainment screen, nicer gauge cluster, etc. Most will also have keyless go, remote start, heated seats and steering wheel, power seat, dual zone climate, etc.
I feel that DFM is a far smoother system than AFM. You really can’t tell when it’s dropping cylinders unless you have aftermarket exhaust. I think it’s a great set up and they did make some changes for 2019 which should improve durability long term. In my opinion, the 5.3 8 speed is a very nice driving combo even though I did buy a 6.2 10 speed.
If economy and purchase price is a concern, don’t overlook the 2.7 turbo either. Impossible to know the long term outlook on either the 2.7 or 3.0 diesel since both are new, clean sheet engine designs. But both return much better fuel economy numbers than the V8s.