Hello, I found a fix for the issue described here. Installing the Files by Google app didn't fix it, but installing the DocumentsUI app did. I'm not an Android expert by any means, but I'm guessing it's needed if your device is running an older Android version (in my case it was an Atoto head unit running Android 10).
https://source.android.com/docs/core/architecture/modular-system/documentsui
The specific APK I downloaded is located here:
https://github.com/hvdwolf/FYTuis7862BinRepo/
There may be a more official location but this is where I was referred from an Atoto forum and it worked for me.
I do realise this thread is nearly 3 years old but adding this reply in the hope it helps someone else.