Done. No issues. The now familiar second restart, at 100% complete.
The latest Realteck WiFi driver provided recently in Window Update still looks weird, showing variable but low signal strength even though the bit rate is good. I guess I was hoping maybe the problem was some incompatibility with the previous 26100.3915 update. Guess not. Or at least, not completely. The bit rate looks better, the little strength symbol on the right side of the task bar still looks like a weak signal.
Realtek's WLAN utility is showing signal strength 96%, while "netsh wlan show interfaces" in command prompt is showing 53% signal, yet still 866.7 Mb/s (802.11ac).