You can do this by adding specific styling for the slider classes.

I checked out the widget via: https://atlasdesignsystem.mendixcloud.com/p/sliders, and noticed you can just increase or add an height property to the rc-slider-rail & rc-slider-track classess.

Note that you might need to increase the height or overall size of some other classess (Such as the rc-slider-handle class, for instance) as well in order to prevent the widget looking weird.