The plugin seems broken, the mouse keep going up by itself, even in a new project with no other plugins.
Tested on MZ 1.10.0 with Dual Sense Controller (The controller is fine, there's no drift, I tested it on steam right after)
Viewing post in R-Stick Mouse MV + MZ comments
Could you check what https://controllertest.io/ shows (for all controllers it reports as connected)?
There were problems before where certain other hardware appeared as controllers with different axes, throwing the plugin off.