The CC2531 has Z-Stack issues (and has had them for awhile now). I’m using the CC2652P2 from here: Tube's ZB Coordinators and Routers (was Zigbee router on steroids?) (https://www.tubeszb.com/product/cc2652_coordinator/1). The best thing about using a Zigbee router with an ethernet connection is that if there is a device that I have to pair in place with a weak signal, I can literally move the router anywhere I need to.
I think your issue might actually be due to power issues at the stick. If I’m reading this correctly, you have a SSD along with a wyze gateway plugged in? It could be that your other two devices aren’t leaving enough nominal power for the Zigbee router. rPis are very finicky when it comes to supplying power to USB2/USB3 devices. The fact that you had a successful pairing off another rPi with just the Zigbee router plugged in leads me to believe that it’s a power problem.