Just hand them a piece of paper of blacked out redacted lines (because confidentiality) and an illegible signature.

I had a district manager once demand I bring in a note after calling in sick. I just told them “No, you don’t pay me enough to go to the doctor and I wouldn’t share any of my medical information with you anyway, you can’t make me.” I never heard anything more about it.

Lots of employers have “rules” on the books that are realistically unenforceable or out right illegal.