You can use this code to Website > Pages > Website Tools > Code Injection > Footer. You can adjust number 2000 in the code.
The code apply for Gallery Page in Well Template Only
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.0/jquery.min.js"></script>
<script>
jQuery(document).ready(function($){
setInterval(function(){
$('span.control.next-slide').click()
},2000);
})
</script>
