Perform Select in UI Designer via API REST with a Process Variable
No, but you may find it easier to write a Custom REST API for this case.
This refers to Subscription but if you export a REST extension you should be able to develop your own for Community.
PS: While this may not be the complete answer you're hoping for, it does indicate a possible solution, please mark as resolved.
But in this example he has in the forum he was able to display the contents of a process variable (In array format) in UI Designer:
But I did not understand how he managed to do this