Simple, change colors only

/* -- START styling Gallery Slider -- */
/* slider previous and next buttons */
a.et-pb-arrow-prev, a.et-pb-arrow-next{
color: #ffffff !important;
}
/* slider controller color modification */
.et-pb-controllers a,
.et-pb-controllers .et-pb-active-control {
background-color: #ffffff !important;
}
/* -- END styling Gallery Slider -- */
Code language: CSS (css)

<https://quiroz.co/divi-image-gallery-slider-skins/>

/* -- START styling Gallery Slider -- */
/* slider previous and next buttons */
.hws-gallery-slider a.et-pb-arrow-prev,
.hws-gallery-slider a.et-pb-arrow-next{
color: #CDBAD6!important;
background: rgba(105,98,152,0.8);
margin-left: -23px!important;
width: 50px !important;}
/* slider controller color modification */
.hws-gallery-slider .et-pb-controllers a {
background-color: #CDBAD6 !important;}
.hws-gallery-slider .et-pb-controllers .et-pb-active-control {
background-color: #696298 !important;}
/* -- END styling Gallery Slider -- */
Code language: CSS (css)