Boot Camp problems on Retina 5k 27” iMac (late 2015) w/ Big Sur and Win10Pro

After much struggling with multiple partition failures and other issues, I upgraded from Catalina to Big Sur and was then able to get a ‘Successful’ Boot Camp install. Initially I was thrilled that I would be able to install and run my very expensive Windows only software on my iMac, but... I quickly realized that multitouch on my trackpad was not working, some standard keyboard keys were not functioning as expected and my external ThunderBolt monitor was not visible to windows. I was able to plug in an old USB keyboard and a USB mouse and get some work done, but then it took some time to figure out how to boot back to MacOS.

The Boot Camp Assistant is not in the windows control icons on the right side of the TaskBar. I have assumed that the missing Boot Camp probably explains the hardware issues as well.

Using the option key to bring up the start disk options when I restarted displayed the McOS disk and two (2) Boot Camp disks. Is it possible that my multiple attempts at creating the portion inadvertently created more than the one that is needed? Might this be a reason for the Boot Camp Assistant not being properly installed in Windows?

Any help would be greatly Appreciated!