Provide a list of usernames who can edit custom field definitions here

acf.php

function remove_acf_menu()
{
 
    // provide a list of usernames who can edit custom field definitions here
    $admins = array( 
        'admin', 
        'jrstaatsiii'
    );
 
    // get the current user
    $current_user = wp_get_current_user();
 
    // match and remove if needed
    if( !in_array( $current_user->user_login, $admins ) )
    {
        remove_menu_page('edit.php?post_type=acf');
    }
 
}