No external playable control of slices from external controllers, unfortunately. It’s a known issue, there is a lag, and you always end up with the previous value. Numerous people have attempted to get around this in various ways, but I don’t know of any successes. You have to play slices directly on the OT. Though you could always set up chromatic notes on the quneo and have the slices on the OT. QuNeo is also good for X/Y control of parameters with OT and things like quickly switching scenes, or enabling the freeze stutter effect with pre determined divisions.
Speaking of, there is a video of multiman controlling the OT with a QuNeo from a while back.
I think he does change slice numbers of tracks, but I believe this is a non-realtime manner, IE, he has the slice looping, and it doesn’t matter as much if the slice number takes half a second to change because it’s quantised with the loop.