Massive collision with a planet bigger than earth may be the answer to Jupiter's unusual core

NASA's Juno probe has provided gravitational readings indicating that Jupiter's core is less dense and more extended than previously thought. This has led researchers, including Rice astronomer Andrea Isella, to hypothesize that a massive impact from a fast-growing young Jupiter, around 4.5 billion years ago, could have caused this anomaly. Simulations suggest that Jupiter's strong gravitational pull made head-on collisions more likely, resulting in a dense impactor hitting the core directly. Such an impact would have spread out the core, diluting its density.

How did Jupiter's strong gravitational focusing affect head-on collisions?

What would be the effect of a head-on collision on Jupiter's core?