/storage/emulated/0/Android/data/edu.mit.appinventor.aicompanion3/files
You should be able to find this with a File Manager on Android 10 (use Total Commander)
This path is built-in to the extension
To EXPORT to ASD you simply add your filename and a slash: /myfile.db
To IMPORT from assets: //myfile.db
To IMPORT from ASD: /myfile.db