Hi!
I personally use the keystation 61 mk3 from M Audio, and as it seems it does send release velocity. It’s relatively inexpensive (you can get one for €130) but you can also get its big brother, the keystation 88 mkII. I suppose it has the same feature, it’s a bit more expensive of course but you get the 88 keys if you really need them.
Good luck with your Kontakt settings!
Cheers,
Eddie