Filter WordPress font_dir directory to change the default font path to /wp-content/upload/fonts

functions.php

<?php

function filter_default_font_directory( $font_directory ) {
    $upload_dir = wp_get_upload_dir();
 
    $font_directory = array(
        'path'    => untrailingslashit( $upload_dir['basedir'] ) . '/fonts',
        'url'     => untrailingslashit( $upload_dir['baseurl'] ) . '/fonts',
        'subdir'  => '',
        'basedir' => untrailingslashit( $upload_dir['basedir'] ) . '/fonts',
        'baseurl' => untrailingslashit( $upload_dir['baseurl'] ) . '/fonts',
        'error'   => false,
    );
 
    return $font_directory;
}
 
add_filter( 'font_dir', 'filter_default_font_directory' );