Exporting a Virtuemart feed using Joomla isn’t easy, especially when you see tons of plugins that haven’t been updated in years.
If you want to create custom labels based off performance you’re basically at a standstill as there’s no way to do that with any kind of Virtuemart module or plugin.
One solution is to use a platform like Feedonomics to feed your VirtueMart products to Google Shopping with best in-class optimization.