Hi anyweez! This is Paige from the Docs team at Replicated. Thanks for your question. We just updated the topic to clarify which properties in the Config custom resource support templating, and which do not: Config | Replicated Docs.
As for your specific question, the hidden property does not support templating. But, you might be looking for the when property, which allows you to use templated conditional statements to show or hide fields from users. You can find more info about the when property on that page in the docs as well: Config | Replicated Docs
I also found what looks like a similar example to what you are taking about (using a specific license field in a conditional statement) in another community post here: Conditional custom fields - #2 by grahamnscp