Again, the context of your question isn't about speed, but more like resistance. There isn’t a single “required speed” that guarantees success against passive abilities like Power Nullification or Existence Erasure. It’s not the deciding factor once you’re dealing with passive, automatic effects, because passive is usually omnidirectional and always affecting everything nearby instantly, and it is not something that is reactable. In this case, you need some resistance to face it.
The speed will matter if the ability has a trigger delay; like the opponent needs to perceive you first or consciously activate the ability. If you're faster than the activation of said ability then you can just blitz them before they activate their passive abilities. But this is assuming if there's a trigger delay.
So it's not about what speed is it, it's about how fast you are compared to that opponent or do you have a resistances against it.