iPhone App FILES does not find files

The iPhone App FILES does not find files. I can click on folders just one level deep and see the files right there, but when I type in the exact name in the search field, it’s like they are not indexed. Is the search feature failing. I’ve noticed this for years. It’s great distressing to not be able to search a file. It’s like the technology doesn’t work. No, it’s that the technology doesn’t work. Can someone please help me with this. This is the most important feature on my iPhone. I access files on my desktop in the documents folder all the time. This is a basic feature. It shouldn’t be having trouble but it’s been years now and it’s still not fixed. Macbook Spotlight has same issues but that’s another topic