Is there a way to add products and variants without the api?
I've seen people create the api call in php like this:
$data = [
'name' => 'Test product',
'description' => 'Lorem ipsum',
$request = new WP_REST_Request( 'POST' );
$request->set_body_params( $data );
$products_controller = new WC_REST_Products_Controller;
$response = $products_controller->create_item( $request );

Why I would like an alternative to your example of rest is you have to actually create the consumer keys, which is a pain for a client if you have a plugin that creates products..

For me personally , I have to check 3 external servers of available products ( plus variants) and update/create products(+ variants) almost every day.. which has to be a plugin that can be shared ..