Thank you for your help.
I am running in to issues with the document when attached to an approval. I've tried the below to try and get the content of the file
first(triggerOutputs()?['body/attachments'])
However, the file attaches visually, and the name is shown correctly, but the file won't open or display, regardless of the file type tested.
I've also tried swapping the below 'name' swapped for 'attachment_content', and it returns this error.

Any advise would be greatly appreciated.