Can't access files on PC that were stored on the SD card of previous phone

Last year I upgraded from a Samsung Note 8 to a Galaxy S25. I ported all my apps, data and files from the old to the new phone, including a lot of files, music, etc. that were on an SD card on the Note 8. Everything transferred fine, and I can access it on the new phone.

BUT...

When I hook up the phone to a PC, I can't see any of the files that used to be on the SD. It's like they're hidden. So, I can't update my music library using drop-and-drag (or any other method I can think of.)

I have "Show hidden files, folders and drives" selected in Windows 11, so that's not it.