What is the use case where your app would need to let the user sort such a large list? I cannot think of any use case. At that point I would let the user set the order field (integer) as it would not be feasible to have a drag and drop UI anymore. That would be cumbersome to use.
It's not 10k but I have Spotify playlists with 4k+ tracks (queue of new albums I listen to as radio at the office) and I always fiddle with the order of the albums at the tail of the playlist.
