@filip.polanowski, I figured out another solution, which is to open the Razer Synapse app, then create a mouse profile for SketchUp with these two inputs disabled. Problem went away. I just have to activate that profile when using SketchUp, which is no more difficult than using an Autohotkey script.
Perhaps those inputs are not recognized as “WheelLeft” and “WheelRight” by my mouse. If anyone has any insight, I’d still be happy to hear it.