boot camp ssd drivers

I have a macbook pro 2020 running Big Sur. I have downloaded Windows on my external ssd. When I load up windows everything's perfectly fine, but I can't use my mouse and keyboard. Running windows setup "setup.exe" and installing the drivers, repairing I can't use keyboard and my mouse. Did anyone had similar problem and managed it? Please help, I really need to run this windows on my ssd.