For a few days now, my 2018 iMac has been dropping WiFi after barely a few seconds of being connected. So it does initially work, but it never lasts unless I turn WiFi off and back on and then it works for a few more seconds.
There seems to be some interference issue because when it stops working, not only can I not connect to the internet using my iMac, but WiFi also stops working on any devices anywhere near it (I have a Mac mini right next to it, and if I have my phone on WiFi nearby - same issue). If I turn WiFi off altogether on my iMac, all the other devices can instantly connect again.
I tried disconnecting all Bluetooth and USB-3 devices, in fact, other than my old wired keyboard and mouse, nothing else is currently connected to my iMac. I also obviously tried rebooting the device repeatedly as well as resetting PRAM and SMC. And I deleted the WiFi connection in network settings and recreated it to no avail.
Any idea what might be causing this? Is this a common issue with these computers?