If we were to add support for reading multiple uploaded files from the form response, would the preference be for Drive URLs as they are exported to Sheets, or for a format with a list of file IDs like @Koichi_Tsuji referenced above? DocId=xxxx , Doc...

You are correct about the 1 file limitation. The existing AppSheet file column types only support a single file. This is documented in Create an app using Google Forms. This note could be added elsewhere in the documentation if there is a place you w...

This integration does not require the use of the AppSheet Events add-on. Events are delivered directly from Google Forms. There doesn't even need to be a Google Sheet linked to the Form.

Thanks for the feedback! Support for Forms file upload questions is coming soon.