WP_Query using pre_get_posts

functions.php

<?php 

function my_custom_queries($query) {
	//Never in admin mode, only the main query(the URL one) and in this case on custom post 'event'
    if ( !is_admin() && $query->is_main_query() && $query->is_post_type_archive('event')) {
        
        $paged = ( get_query_var( 'page' ) ) ? absint( get_query_var( 'page' ) ) : 1; //URL /page
        
        //For URLs like so:
        // www.url.com/events/type/all/category/all/artists/all
        //ignore the all var
        $type = ( get_query_var( 'type' ) && 'all' != get_query_var( 'type' ) ) ? get_query_var( 'type' ) : null;
        $category_name = ( get_query_var( 'category_name' ) && 'all' != get_query_var( 'category_name' ) ) ? get_query_var( 'category_name' ) : null;
        $artists = ( get_query_var( 'artists' ) && 'all' != get_query_var( 'artists' ) ) ? get_query_var( 'artists' ) : null;
        	
    	$tax_query = array();
    	//create filter for custom taxonomy type
        if (!is_null($type)) {
    		$tax_query[] = array(
				'taxonomy' => 'type',
				'field' => 'slug',
				'terms' => array($type)
			);
		} else {
			 //Force WordPress remove this filter when we pass all as paramester to the WP_Query
			$query->query_vars['type'] = null;
		}

		//create filter for category
    	if (!is_null($category_name)) {
    		$tax_query[] = array(
				'taxonomy' => 'category',
				'field' => 'slug',
				'terms' => array($category_name)
			);
		} else {
			//Force WordPress remove this filter when we pass all as paramester to the WP_Query
			$query->query_vars['category_name'] = null;
		}
		
		//create filter for custom taxonomy type
    	if (!is_null($artists)) {
    		$tax_query[] = array(
				'taxonomy' => 'artists',
				'field' => 'slug',
				'terms' => array($artists)
			);
		} else {
			//Force WordPress remove this filter when we pass all as paramester to the WP_Query
			$query->query_vars['artists'] = null;
		}

		if ( count($tax_query) > 1 ) {
			//if more than 1 tax_query, let's put and AND parameter
			$tax_query['relation'] = 'AND';
		}
		
		//Giving the new parameters to the main WP_Query
	    $query->tax_query->queries = $tax_query;
	    $query->query_vars['tax_query'] = $tax_query;
		
		//Filtering using a custom date (Ymd) as a meta_query(custom field)
    $today = date('Ymd');
		$query->set('meta_query', array(
		  array(
  			'key' => 'custom_date',
  			'value' => $today,
  			'type' => 'numeric',
  			'compare' => '>=' //starting from today by a custom field
		  ) //put more meta_query filters here if you need
		));

    $query->set('orderby', 'custom_date');
    $query->set('order', 'ASC');

    $query->set('paged', $paged); //to get from the URL or just the first page
        
    //Make any filter you want using WP_Query with $query->set()


    } /* Make a elseif() for other custom post archive or any page you need using the conditional tags */
}

add_action( 'pre_get_posts', 'my_custom_queries');