Hello Lousse Jérôme,
There are no such option for limiting the number of the links of the breadcrumb or hide in mobile devices only.
But you can add height to the inner banner so that it does not disappear under the navigation bar.
Please follow the path below:
Appearance > Customize > Header Options > Header Image
Under Inner Page Header Section Height title you will see slider option to increase or decrease height of inner banner.
(Note:It will increase or decrease height in all devices)
Or for quick fix you can just remove breadcrumb form smartphone. Please add the following Additional CSS.
Appearance > Customize > Additional CSS
@media(max-width: 767px){
.inner-main-title .breadcrumbs{
display : none !important;
}
}Best Regards!