Isn’t Returning Value While Using SELECT COUNT(*) FROM {$wpdb->prefix}

 $combined_views = (int)$get_visit_query + (int)$offset;

This doesn’t make much sense. $get_visit_query is a string (your query). Converting it to int returns in 0, see this snippet. Instead it should be

$combined_views = (int)$visits_total + (int)$offset;

Sidenote: Are you actually hooking the function via add_filter()? If not, apply_filters('get_post_views', ..) will not have the desired effect. Using the function name doesn’t magically add it to the filters, you need to explicitly define it e.g. via add_filter('get_post_views', 'get_post_views', 10, 2);.