Add Sanitize Filename to Plugin: Media File Renamer (Auto Rename) By Jordy Meow

sanitize-filename.php

<?php

/* https://wordpress.org/plugins/media-file-renamer/ */

add_filter( 'mfrh_new_filename', 'my_filter_filename', 10, 3 );

function my_filter_filename( $filename, $old, $post ) {

    $sanitized_filename = remove_accents( $filename ); // Convert to ASCII

    // Standard replacements
    $invalid = array(
        ' '   => '-',
        '%20' => '-',
        '_'   => '-',
    );
    $sanitized_filename = str_replace( array_keys( $invalid ), array_values( $invalid ), $sanitized_filename );

    $sanitized_filename = preg_replace('/[^A-Za-z0-9-\. ]/', '', $sanitized_filename); // Remove all non-alphanumeric except .
    $sanitized_filename = preg_replace('/\.(?=.*\.)/', '', $sanitized_filename); // Remove all but last .
    $sanitized_filename = preg_replace('/-+/', '-', $sanitized_filename); // Replace any more than one - in a row
    $sanitized_filename = str_replace('-.', '.', $sanitized_filename); // Remove last - if at the end
    $sanitized_filename = strtolower( $sanitized_filename ); // Lowercase

    return $sanitized_filename;

}