After review with @Tayebsed93 , we found a technical issue:
As the component propose an API for its initialization without providing step increment, it is not to possible to define properly the actions of the + and - button. Indeed, those actions should compute the new value incresing or decreasing the current value with the step....

As it is the current behaviour of the native component, what we can propose ?
@B3nz01d , @mccart77 , @pya35