Private attachments are public in /wp-contet/uploads

Hi there,
I noticed if a user submits a file to the form. The file is uploaded in something like https://example.com/wp-content/uploads/2022/08/file.png and is there publicly available. As this is really difficult to handle with private data is there anyway to disable this upload and just attach the file to the e-mail or is there another way to keep the form data private? Also a deletion right after the send out would be a way to go. How to proceeed here?
Thanks and kind regards