Change the next and previous post links sort order and filter out expired events for single espresso_events post types. Requires EE4 + a theme that uses the native next_post_link() and previous_post_link() functions.

adjacent_posts_filter.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

add_action( 'template_redirect', 'ee_custom_filtered_adjacent_post' );

function ee_custom_filtered_adjacent_post() {
    add_filter( 'get_next_post_join', 'ee_custom_filtered_adjacent_post_join' );
    add_filter( 'get_previous_post_join', 'ee_custom_filtered_adjacent_post_join' );
    add_filter( 'get_next_post_where', 'ee_custom_filtered_adjacent_post_where' );
    add_filter( 'get_previous_post_where', 'ee_custom_filtered_adjacent_post_where' );
    add_filter( 'get_next_post_sort', 'ee_custom_filtered_adjacent_post_sort' );
    add_filter( 'get_previous_post_sort', 'ee_custom_filtered_adjacent_post_sort' );
}

function ee_custom_filtered_adjacent_post_join($sql) {
    global $wpdb;
    if ( !is_main_query() || !is_singular( 'espresso_events' ) ) {
        return $sql;
    }
    $sql .= ' INNER JOIN ' . EEM_Datetime::instance()->table() . ' ON ( p.ID = ' . EEM_Datetime::instance()->table() . '.' . EEM_Event::instance()->primary_key_name() . ' ) ';
    return $sql;
}

function ee_custom_filtered_adjacent_post_where($sql) {
    global $wpdb, $post;
    if ( !is_main_query() || !is_singular( 'espresso_events' ) ) {
        return $sql;
    }
    $sql .= ' AND ' . EEM_Datetime::instance()->table() . ".DTT_EVT_end > '" . current_time('mysql', true) . "' ";   
    return $sql;
}

function ee_custom_filtered_adjacent_post_sort($sql) {
    global $wpdb;
    if ( !is_main_query() || !is_singular( 'espresso_events' ) ) {
        return $sql;
    }
    if ( current_filter() == 'get_next_post_sort' ) { 
        $sort = 'ASC';
    } else {
        $sort = 'DESC';
    }
    $sql = " ORDER BY {$wpdb->prefix}esp_datetime.DTT_EVT_start {$sort} LIMIT 1";
    return $sql;
}