Welcome to the Make community!
I am able to use the system inputs to change the GPT output. Perhaps it might be a misconfiguration on your module.
Could you please share screenshots of the module fields and/or filters in question? It would really help other community members to see what you’re looking at.
You can also export the blueprint file to allow others to replicate the issue. At the bottom of the scenario editor, you can click on the three dots to find the Export Blueprint menu item.
Uploading it here will look like this:
blueprint.json (119.3 KB)