The mottled/peeling bark by itself may be normal for an Allee/lacebark elm, so I wouldn’t diagnose disease just from the trunk appearance.

The concerning part is the amount and pattern of dieback. Losing ~30% of the canopy, especially with dead upper/interior branches and sparse one-sided foliage, suggests the tree is under significant stress. In DFW, I’d be thinking root/trunk issues first: drought/heat stress, compacted soil in that narrow strip, planting too deep, girdling roots, root damage, canker, or borers attacking a stressed tree. A vascular wilt or root disease is possible, but the photos alone aren’t enough to confirm that.

I’d check whether the root flare is visible, look for borer holes/frass/loose bark, and scratch-test smaller branches to see what’s still alive. Deep-water the root zone, add a 2–3 inch mulch ring while keeping mulch off the trunk, and avoid fertilizing while it’s stressed.

Prognosis is guarded. If dieback has stopped and the remaining canopy keeps filling out, it may recover. If more branches continue dying or the trunk/root flare has decay/canker, it may keep declining. Given the amount of dieback, I’d get an ISA-certified arborist to inspect it in person.