Template in Sheet Builder
Add a Template method block in Sheet Builder when different records need different Illustrator templates. Choose the template path and apply the editor to the sheet, then preview through Data.
Use one path column for each block. Choose the template with the Path field. Put a common folder in the property default and only filenames in the records.
For example, use path: {{DATA}}/../Templates/ in the property header and label-small.ai or label-large.ai in the records. Keep those template files beside the delivered data and verify the resolved paths in the target workflow.
The editor only changes the sheet; applying it does not open or export every template. See Template for template selection behavior.
Editor controls

Captured from the running Darty-Ai extension in Illustrator.