Hi @LexiaAlistair - great to see you here! :)
We indeed don’t have a specific pre-moderation feature for attachments that would require a moderator to approve the post (with attachment) before it appears in the community.
If I’m understanding the use case correctly, I can think of one approach that might help with this use case. I’m making an assumption that you want to minimise the risk of inappropriate files being uploaded. If so, rather than giving all registered users the permission to upload files, you could disable the permission by default and create a custom role with the permission ‘Upload files to posts’ enabled. This custom role could be granted automatically to members using a rank. It would be a kind of ‘perk’ that you only get once you’ve passed a reasonable threshold of participation, at which point you’d likely be a trustworthy member. Would that approach help meet your use case?