Proper way to get label from system.xml

Question

I have a form in the store -> configuration what I've created in my system.xml.

Before save I want to validate it. When an error happens, I want to inform the user what field was not valid.

How can I read out the label of the field from a Magento\Framework\App\Config\Value in the beforeSave method?

Now I can read out like this:

$label = $this->getData('field_config')['label'];

But is this the proper way to get the label? Isn't there a method or cleaner way to do it?