Combine two filters into a single call

As long as the received arguments and the return values are the same, yes, you can combine them.

add_filter( 'manage_edit-post_columns', 'my_columns_callback' );
add_filter( 'manage_edit-recipe_columns', 'my_columns_callback' );
function my_columns_callback( $columns ) {
    $columns['author'] = 'User';
    return $columns;
}