How to merge PDFs (where the number of PDFs are unknown)

This workflow is exactly described here:

youtube.com/watch?v=tPnUMLa7sYA

However the problem is this requires the number of PDFs to be known in advance.
However in my case I need to get all PDFs inside a Google Drive folder and combine them - and the number of PDFs can be anything from 2 to more than 100.

This won't work as described in the video because the location of the job details ID will change. So how can I customize this to merge all files in the folder?

My workflow is here:
https://connect.pabbly.com/workflow/mapping/IjU3NjUwNTY5MDYzNTA0MzI1MjZjNTUzNTUxMzci_pc

In addition I get this error from CloudConvert:
When calling your webhook https://connect.pabbly.com/workflow/sendwebhookdata/IjMyNzk3Ig_3D_3D we have got the following error:

HTTP/1.1 410 Gone returned for "https://connect.pabbly.com/workflow/sendwebhookdata/IjMyNzk3Ig_3D_3D". Response body:

I managed to solve this as it turns out the JOB ID field value remains the same - so i can just refer to the JOB ID I get.

UPDATE: It is not working still.
I still get this error - and the webhook gets disabled in CloudConvert.
When calling your webhook https://connect.pabbly.com/workflow/sendwebhookdata/IjMyNzk3Ig_3D_3D we have got the following error:

HTTP/1.1 410 Gone returned for "https://connect.pabbly.com/workflow/sendwebhookdata/IjMyNzk3Ig_3D_3D". Response body:

CloudConvert automatically disables webhooks if they produce a 410 error response or if they fail for 7 consecutive days. You can enable the webhook again in your webhook settings:

Please share the Task History ID in which you have received this error.