I'm hoping to get it on the bottom. I edited some of your code but the arrows get cut off.
Here's what's in there now.
/* Mobile slideshow arrows */
@media screen and (max-width:767px) {
.user-items-list-item-container[data-section-id="613a80048018bf0166ef11b7"] {
.mobile-arrows {
margin: 0px !important;
}
.mobile-arrows {
position: absolute;
top: 88%;
transform: translate(-50%,-50%);
width: 35%;
left: 50%;
margin-top: 65px !important;
justify-content: space-between !important;
}
}}