The Google Picker cannot filter by “files created by my app” (drive.file) out of the box. The Picker’s Drive view does not support Drive v3 query syntax (like appProperties) nor any “creatorAppId” filter. The setAppId and setQuery you tried won’t achieve this.

What you can do instead:

Use a dedicated folder for your app’s files, then point the Picker to that folder.
When you create the spreadsheet, place it in a known folder (e.g., “MyApp Sheets”).
In the Picker, use DocsView.setParent(folderId) so users only see files inside that folder.