I normally play in full screen mode and after updating to Big Sur I noticed my mouse pointer icon was significantly larger (roughly 3 times in size). This was only in full screen mode, in windowed mode the cursor was the same size as it was pre-installation. Everything else in game stayed proportionally correct when switching between screen modes except the mouse pointer.
I was able to correct this by manually changing the cursor value from -1 (auto detect) to 0.
/Console cursorSizePreferred 0
iMac (Retina 5K, 27-inch, 2020)
3.8 GHz 8-Core Intel Core i7
32 GB 2667 MHz DDR4
AMD Radeon Pro 5500 XT 8 GB