Answer not given here, but apparently inserting "manually" the tags in the text in the same format as the custom macros in Classic UI should work. I will test and let everyone here know if it works as a workaround until it is natively added.
The new designer does not yet have the ability to display information with advanced macros as it was in the old designer (first name, etc.).
We are still working on advanced macros implementation in the new email template builder, we believe that this option will be available in the near future.
Please note that the old designer is available for use and you can work with it.
