Peter
Your problem sounds like it may be a Virtual Comport Manager (VCM) Problem. I have found- through experience- that more than one VCM on your computer may cause you problems. For example, the Virtual Comports created by VSP Manager, and those created by Microbit Setup Manager, may not coexist on the same computer without problems. The Microham Virtual Comport Managers may not coexist with other VCMs. Notice, I say, may- sometimes ops may have them on the same computer with no problems, other times they won't work from day 1. I've even seen it where problems don't exist today, but a week from now they do. In its installation instructions, VSP Manager tells you to remove all other Virtual Comport Managers off your system before you install it. The one way communication you describe with the radio leads me to believe that you may a conflict with VCMs.
My suggestion is to look at your system in Device Manager, and see if you have multiple VCM. If you do, do you need all of them? In particular, I'm not sure why you leave your K3Mini connected to USB all the time- I've found no need to do so with mine. I do use the Microbit USB cable and do radio control through Com2 of it, and use ComExtra for the Winkey in the RRC, so I don't leave my K3Mini connected to USB (and the comports are never created for it).
It also sounds like you updated from Winxx to Win10, then tried your apps. I'd also suggest you uninstall, then reinstall the Microbit Setup Manager if you haven't already done so; there may have been a glitch that prevented Win10 from realizing that those comports. I would also do it in this order: disconnect the Microbit USB cable, reboot the computer, uninstall Microbit Setup Manager, reboot, then reinstall Microbit Setup Manager.
I'm not a computer professional, but have just been stung too many times by VCM programs that can't work together. Any one of them will work fine, but when you put a second one on the computer the chances there will be problems goes way up.
Dennis W1UE