If the Ragna is far enough away and you normal block Dead Spike, it's safe to throw out a 5A, because if they run in to apply more pressure, that's gonna take enough time to where they give up their frame advantage just to get close enough to you. In this case, our 5A is faster than Ragna's 5B or 5C and will beat it out.
This is situational though, since I can't guarantee it will work if they don't dash in first, but it's a whole hell of a lot safer than hitting 6D after blocking deadspike.