Multiple folders and all of their content in my notes app disappeared and I didn’t delete them

Most, but not all, of my notes suddenly disappeared. I didn’t delete them. They’re not in the recently deleted folder, I checked icloud.com just in case but they also weren’t there. Nothing else of my iPhone 13 is out of the ordinary, but practically all of my important notes are gone without a trace. Is there any way I can bring back permanently lost notes?

I also want to know what caused them to suddenly disappear.