Missing Music

Why are many of my previously purchased music missing? I have listened to the songs for many years, but now they are gone from all my devices. I have never had another account, so it's not that I purchased them with a different account.

When I search, they're not even in the iTunes store. I paid for them. Where are they? I have had an apple ID for many years.

I've followed these instructions:

If there's an issue when you redownload apps, movies, or other content from Apple https://support.apple.com/en-us/HT211842

Redownload Music https://support.apple.com/en-us/HT211816

I don't have a subscription to Apple Music, and shouldn't need one since I purchased my music years ago.

I have several devices, and they all have the same set of songs. They are all missing the same songs.