I had this problem too, using my Magic Mouse 2 in my Bootcamp Windows 10, and looked all over for a solution. It showed that I had the Magic Mouse 2 paired in my Bluetooth settings, but the mouse just didn't work.
This solution worked perfectly for me:
Download the driver from here:******
All I had to do was download, then double-click to install. Note, when it asks if you're installing on a mac, answer 'no'. Then follow the rest of the directions.
I didn't have to do any other bootcamp installs/reinstalls or anything else.
Happy Magic Mousing in Windows 10!
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