You can export the original from the Lr mobile app but this can only be done on individual images, and it doesn’t include the edits. 99jon suggestion is your best option. You could also try logging into lightroom on the web at lightroom.adobe.com. I’m pretty sure this works with the premium mobile subscription, but the features aren’t as robust as using the actual Lr CC app.
Upgrading to desktop LRCC would cost me another 12€/month. So not the ideal Solution. thought i could work arround by using the Creative cloud App where I also can see the LR-Photos but again only can download picture by picture. Using the Creative cloud web application don‘t show the LR-Fotos. So in total I‘m still stucked. Not the best work of ADOBE. 😞