Leave login URL for my user beautiful

Assuming you’re trying to get rid of the ?redirect_to={url}, you can use the login_url filter to change the login URL, and remove unwanted querystring components with remove_query_arg():

add_filter( 'login_url', 'wpse422493_strip_login_url' );
/**
 * Strips `redirect_to` from the querystring.
 *
 * @param  string $url The login URL.
 * @return string      The filtered login URL.
 */
function wpse422493_strip_login_url( $url ) {
    return remove_query_arg( 'redirect_to', $url );
}

Note: This code is untested and intended as a starting point only, not as finished, production-ready code. Make sure you test it in a non-production environment before you use it in production.