I see you where you are going.
For all practical purposes. It will be very costly to launch 100s of long range BMs when most can get intercepted by planet's only credible missile defense system. Unless those are hypersonics (with variable trajectory).
Secondly, I don't think Pakistan feels the need OR has guts to attack Israel. Its not going to happen.
However, If we ever decide to go against Israel then we have a lot easier solution. Just partner up with Iran in their next round with Israel. Iran will do all the BM stuff and we just provide Iranian airspace defense with our airforce. It's also much acceptable to world as we are not being aggressor. We are just providing airspace defense for "brotherly" nation. Just like US & europeans provide protection to their ally Israel against Iranian BMs. That's the least / most practical thing we can do to do our contribution. But honestly I don't see us doing even that.