Mouse
I have a new iMac and the mouse is inconsistent jumps. How do I fix it?
iMac 27", macOS 10.14
Question marked as
If your pointer is jumpy when you use a trackpad, Magic Trackpad, or Magic Mouse - Apple Support
Additionally, go to System Preferences > Mouse and change your tracking speed.
Test with another mouse and see if it works as expected.
You have 14 days to return a new Mac for a full refund. I think you could do same with a mouse if that's the problem but you'd need to check with Apple.