It seems that the installation fails when attempting to install from the zip on QGIS 3.4.13. Also the plugin is not visible in the plugins repository even though experimental plugins are shown.
I tested QGIS 3.4.13 inside docker. The plugin is available in the plugins repository and the installation works both from there and from newest 0.4.0 release zip.
It seems that the installation fails when attempting to install from the zip on QGIS 3.4.13. Also the plugin is not visible in the plugins repository even though experimental plugins are shown.