Due to Android API 29 changes noted here, here and here, the export won't work as noted in version 1 (see below). Because of these permission changes, export data for Android won't work as it used to work. Also, the rights for EPPlus have changed after version 4.5.3.3. As such, this change had to switch away from EPPlus to Microsoft's DocumentFormat.OpenXml.
Version 1 - see blog article.
To get the source for this version 1 use tag 1.0 here and use the zip download.
The source for this is released under the MIT license.