@PsYChiC: That did not have any effect. Do you have any other ideas?
About the same time the 1.23.9.10145 update was released, I replaced a WiFi 5 dual-band router with a WiFi 6 dual-band router (2.4 GHz and 5Ghz under same network name). I keep reading that dual-band setups cause problems, but since I had no problem with the old one, I worry that splitting the bands onto separate networks on the new one will have no effect either. Thoughts?