I’m using imwheel successfully, with the following .imwheelrc config file, only affecting mouse scroll wheel in Brave Browser:
"^brave-browser$"
None, Up, Button4, 3
None, Down, Button5, 3
Control_L, Up, Control_L|Button4
Control_L, Down, Control_L|Button5
Shift_L, Up, Shift_L|Button4
Shift_L, Down, Shift_L|Button5
Start imwheel as follows as to not affect the “back button” on the mouse:
imwheel -b 45