You can use the formula below in the Calculated Fields to filter the order timeline entries (aka "order events") and only include those related to "shipping_labels" actions:

"\n".join([i.created_at + " [" + i.action + "] " + strip_html_tags(i.message) for i in load_json_data({{ events }}) if i.action.startswith("shipping_label_")])

There's also a template called "Orders with Shipping Label Events (Last 30 Days)" you can use which already includes this formula and can be customized further.