My first thought about that is you'd need a lot of satellites already nearly co-planar with the ICBM's inclination and there probably aren't enough Starlinks in any given inclination to make that realistic (granting secret dV and a sporty enough TWR). Boost phase is pretty short.

yeah the guy I was watching was talking about needing 3Gs of acceleration to intercept if it's not too far away

This is the context I was thinking about https://youtu.be/XDXKRQCkvms?si=1P8eLrZcPiP_ZSHw&t=353