How can I make it so that all images that were once uploaded in the project will be shown there? Why isn’t the type: files not doing it? Is there another way to show all files inside the project?
The purpose of a files field like in your example is to select files from files uploaded to a page. So it is basically a select field, but especially made for files.
To display all uploaded files you need a files section.
Yes, ok, that is a section now, but you filter what is shown with the gallery template. This will only show files with this template/blueprint. The template is added to the meta data file on file upload. If you add the files via the file system manually, the template will not be added and the files will therefore not show up unless you add the template manually.