Hi Pixolin,
The snaps don’t update via the updater app, they have their own mechanism where you don’t have to do anything for the snap to update. You can expect Nextcloud 11 in the snap some time early next year. It takes extra time to built and test that and we first want to release the image for the Raspberry Pi 3.
@grzegor in reality, very few people use the encryption app and none of our customers do. So, as @BernhardPosselt pointed out - this is in the end a community driven project. As in, if somebody does the work, it happens. I do believe there are discussions about doing something around encryption for Nextcloud 12, though, so perhaps this will get tackled. But no promises.
By the way, you can use the Encryption app with an object storage, in that case no file names are leaked. There is a work-around, thus. With regards to the UUID, that is what the object storage does and I suppose it would be possible to adapt it to the encryption app somehow. But it would require a major re-architecture of how external storage works, from what I can tell. In any case, perhaps for 12 or 13. We have plenty releases ahead of us 
Thanks for caring!