This extension does generate individual URLs for each file in the attachment field. You can modify the index in the URL to access a specific file within the field. The index begins at 1. Here is an example URL.

https://web.miniextensions.com/api/public-attachments/l9v2rOh9nqDPG1z8OVzi/rec1xGA04dDbrQjxb/1
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You just need to change the number at the end of the URL to change the index.

If the URL does not include the index number, it will function as before and display the first file in the attachment field. You can just add the new parameter in your existing URL if you want to change it to another file in the field.