Hello,
It's super hot here in SoCal; my Chinese elm had its leaves turn brown and crispy and then fall off. The bark is still green, and even the smaller branches, if I check, are green. It seems to be in some holding pattern. It's been over a week, and it's just leafless.
Also, soil is moist but not soaked, been checking with a meter and no need to rewater, water uptake very slow.
If the bark is still green, I would say move it to a place where it can get some consistent indirect sunlight. Try to keep the temperature as steady as possible under a bigger tree where it still gets some spotted sun but is protected under a larger canopy. In Socal, especially this last week, the temperature spiked a lot. A few of my trees started to get a bit crispy.