I guess you need to use hook_views_query_alter and then you could add your OR condition.
function hook_views_query_alter(ViewExecutable $view, QueryPluginBase $query) {
if ($view->id() == 'machine_name_of_your_view' ) {
//$query->where contains the filter conditions
//i.e. AND'Where' part of the query where you could add yours.
print_rvar_dump($query->where);die;
}
}