Thanks for the additional Logitech info.
After updating the Realtek driver (WHQL-provided, v 10.6.1001.2015, 10/1/2015), the problem seems to have resolved. It had been intermittent, however, and at times the system would go for several days or weeks without incident. So, my plan is to update nothing else at the moment, and wait to see whether this is indeed the solution. If not, I will advance to removing the Logitech software.
Incidentally, before coming to this forum, I had applied, over at least a year's time, a number of Intel wi-fi and Bluetooth driver updates for the AC-7260 adapter. None resolved this issue, and some introduced other odd, unreliable behavior. In the end, the Microsoft-supplied WHQL drivers (wi-fi v 18.33.9.3, 10/1/2017; Bluetooth v 29.90.1.1, 10/8/2018) proved the most reliable.
So, we wait and troubleshoot one potential solution at a time. Many thanks again for your help.