Also, Nextcloud/Owncloud are written in PHP, that might also have a significant impact on its poor reliability ^^

I initially thought the same. I finally upgraded my phone this year and since the new phones have the button I just tried it out and ended up really liking it. I would consider myself a photography enthusiast though, so I can see this is not for everyone. It just feels more like an actual camera. The position is still awkward, though