It is -1 at worst without dash cancelling, dash cancelling seems to put it around +7, I've purple grabbed off it in training mode. The New Deadspike seems to be wonky with it's hitbox, or rather really spacing dependent. It's growing on me though.
I found something interesting (though I'm sure this was known in CSE, but it's new to me).
Off close range 6D, if you cancel into BE, it seems to hit on the very last possible active frame, and it looks like it actually skips the hitstop on Ragna. Doing dash 5A/2A after it feels like a super tight block string.