I own a Varmilo VA87M, and recently my keys all got mixed up when flipping the board. Thanks, gravity.
On my keyboard, the Left CTRL/Caps Lock and FN/Windows got swapped.
Fix for Windows and FN key
First, hold down both Windows key for 3+ seconds. It should flash 3 times when done.
Fix for Left CTRL and Caps Lock key
After that you can fix the Left CTRL key and Caps Lock key by holding down the FN key and Caps Lock key for 3+ seconds. It will flash 3 times when done.