I changed it with a new RSHTech 7-port USB hub, plus the black-display screen reboots continue. I'm stumped at this moment, essentially starting to suspect my UPS of spikes or momentary cutouts. in any case I think the https://lewiszvml949981.mybjjblog.com/the-smart-trick-of-iogear-2x4-usb-3-1-gen-1-type-a-peripheral-sharing-switch-that-nobody-is-discussing-41989884