Hi Robert,
The only thing I can think of is to try your other display and see if the adapters work with it. Also, are you using exactly the same adapters? (See below)
Can you see what version of firmware your Apple adapter has? This didn't matter much for me, I have two adapters that work, one has version 1.03 and the other has version 1.01, but perhaps the firmware version may be affecting your set-up differently?
I've seen the display go dark while still being recognized by the computer, but I don't think it is the same as what you're experiencing. For me, it usually seems to happen after I've stepped away and both the laptop and 30" display have gone to sleep. I'll come back and open up the laptop and on the laptop display, I'll see the windows I expect to see when the big screen is working, rather than all of the windows crowded onto the laptop, which happens when I'm not connected to the big screen, and my cursor can go off screen into the territory where the big screen should be, but the big screen is still sleeping, and won't wake up. I usually have to restart to get the display to work with the computer again.
Adapters that don't work: I have been trying to get a second 30" display working, so I'm still shopping for connectors to make it work. Since I have a working set of cables, I can test new parts pretty definitively. The Goo-quee adapter I have has jumped in price from $15 to $25, so I've been looking for a cheaper option. I bought two different USB-C to displayport female adapters (for $8 or $9 each) and neither one works. In both cases, the 30" display is not recognized and doesn't light up, but when I take them out and put in the goo-quee adapter back in their place, the display fires up and works normally. Oddly, when I contacted the sellers about a refund, both said the same thing. "Sometimes our adapters are defective. We'll refund the purchase price. Don't bother returning the item."
The Goo-Quee is white and has a little circuit board inside the female display port end. Both of the adapters that don't work have black molded plug-ends. It doesn't look like there is room for a circuit board inside the molded plug ends. See photo below.

(Here's a photo of the goo quee adapter that works for me and the Tech Orbits adapter that doesn't.)
Here are the details for the two adapters I tried that did not work:
1. eForCity BasAcc USB Type-C Adapter, USB-C to DisplayPort Female SuperSpeed White
2. TechOrbits USB 3.1 Type C (USB-C & Thunderbolt 3 Port Compatible
I'm sorry your displays aren't working for you. It's extremely frustrating, I know. I wish I could be of more help. Good luck! Please post if you figure out how to get your display(s) working.