I had no problems with USB to CI-V converters when changing from Windows XP to Windows 10 years ago. And I haven't had any problems over the years with Win 10 upgrades affecting CI-V operation. Perhaps you have a problem with the CI-V port in the radio. The 3.5mm jacks are easily damaged internally when plugging and unplugging cables. The contacts can be bent and the SMT leads can be pulled loose from the PCB pads if excessive force is applied to the plug's body at an angle.
Have you verified the radio's CI-V settings in Menu items 48-50 match the COM port's baud rate and the programs' settings? Also verify the program is using the correct COM port.
I don't believe this is an inherent problem in Windows 10. All versions of Windows have been a little quirky in releasing a COM port when the device or program teminates a connection sometimes. My AIM antenna analyzer port has problems with this. Sometimes just waiting 10+ minutes between stopping the software and restarting it allows the port to be released so that it can reconnect OK. Other times even a reboot doesn't release it and I had to disable the port, reboot and then enable the port. But most of the time it works fine. Swapping back and forth between cables with different USB chips in them can confuse Windows sometimes. I had two similar but different USB to Bluetooth adapters that had this problem. As long as I used the same adpapter for an application then all was well.
There used to be problems with Windows trying to use a previously installed USB chip's driver instead of the newer one just installed. I haven't seen this in Windows 10, but I haven't changed USB adapters much either. It is best to uninstall an older FTDI or other USB driver before installing a new one, unless there is a known reason the older driver is needed for some device. In Windows XP I would always uninstall the old driver, then if some device wasn't compatible with the newer version I would decide whether to reinstall it or update the hardware adapater to use the newer USB interface chip.
Good luck resolving the issue.