For thumb buttons for mice like the MX Master 3S, you can create custom gestures. Please allow zoom in/out to be an option for thumb button + up and thumb button + down when you create custom gestures. It is already available specifically for the "zoom/rotate" gestures preset. Please bring it to the custom gestures side as well. I'm already aware of "smart zoom" being an option but it isn't the right choice for myself. Thank you!