I have a lot of notes with images and every time I create a new note I have to create a new folder for the image, I know that I can create any structure, but this is a routine.
I have a separate folder for attachments and by default everything is saved there in a flat structure.
I think we’re talking about two different things. It’s clear to me now that you and OP are referring to an automatic file system structure creation. That was not clear to me from his original post.
When I said “You can have any structure you want” I was referring to the manual creation of folders for attachments, which can take any form. I don’t use the Obsidian Attachment folder tool. I keep mine in my structure.