Shamim's Plugins

I see your are not using latest version of the plugin. Please update to latest version and it will work.
I have manually renewed your previous license, So in this plugin version you can use previous license now and can update.

You need to change $args parameters only. Not full get_users function.
Eg.

add_filter( 'fep_filter_rest_users_args', function( $args ){
    $args['search'] = 1449,
    return $args;
});

Please follow https://www.shamimsplugins.com/docs/front-end-pm/integration/multilingual/

Can you please set “V2 checkbox” captcha and set new site and secret keys (both in google and settings page of this plugin) and try?
Let me know.

Can you please give me your website contact form url?

Yes, also you can add/unset any parameters if you want from $args. So if you want to unset exclude parameter you can use unset($args['exclude']).

You can use fep_filter_rest_users_args hook.
As $args is supplied to get_users function you can modify any parameters there. you can get supported parameters in https://developer.wordpress.org/reference/classes/wp_user_query/prepare_query/

It is added but not yet released. If you know how to change from git commit you can see https://github.com/shamim2883/front-end-pm/commit/25abae8891de1707324e54575eacbc3551a6eeca