Use this custom CSS

@media (max-width: 767px){
.sp-slider #sp-slider-item-1657564847607-num-0-key #sp-slider-inner-item-1657564847608-num-1-key {
   font-size: 15px !important;
    white-space: nowrap !important; 
}
    .sp-slider #sp-slider-item-1657564847607-num-1-key #sp-slider-inner-item-1657564847609-num-1-key {
   font-size: 15px !important;
    white-space: nowrap !important; 
}
    .sp-slider #sp-slider-item-1657564847607-num-2-key #sp-slider-inner-item-1657564847610-num-1-key{
   font-size: 15px !important;
    white-space: nowrap !important; 
}
}

Path towards custom CSS: Extensions>Templates>Styles> Click on your current default template name then choose Template Options. Then find custom CSS within the custom code.