If you want to disable the manual input of the spinbox, then I would suggest to use a simple slider rather than a spinbox, and the you can customize your slider by applying a dynamic material on it.
In that way you remove the manual input feature, disable the keyaboard on mobile, and you can custmize even more than a spinbox. In my opinion using a slider and apply a dynamic material is the best solution.
Here a video which explain step by step how to make and apply a custom material on a slider:
Good luck with your project !