change the author link

add_filter( 'author_link', 'jeg_modify_author_link', 10, 3 );
function jeg_modify_author_link( $link, $author_id, $author_nicename ) {

    /* get the real username */
    $username = get_userdata( $author_id );
    $username = $username->data->user_login;

    /*
    change local with your author username
        change the test-page with your page link
        you can add more if statement for all you author
    */
    if ( 'local' === $username ) {
        $link = get_home_url() . '/test-page';
    }
    if ( 'local' === $username ) {
        $link = get_home_url() . '/test-page';
    }
    if ( 'local' === $username ) {
        $link = get_home_url() . '/test-page';
    }
    return $link;
}