Thanks for bumping this up, @kp8, and for the original post, @Emad_Heydari_Beni. As you can see from this other thread, the request to support other cloud storage providers is not new and there is reasonable demand for it.
We do intend to develop beyond the Google ecosystem (for other features as well, like authentication) but had not found ourselves in a position to do so until now. While there are no concrete plans for this at the moment, the release of our apps has given us more flexibility to consider and prioritize other topics and this one’s on our radar.