> Boltzmann’s model also ignored the influence of gravity, which is often described as an anti-entropic force due to its clumping effects on matter.

I never heard something like that. Gravity follows the first and second laws of thermodynamics.

>> gravity, which is often described as an anti-entropic force

I don’t know about that but it’s also sometimes described as an entropic force https://en.wikipedia.org/wiki/Entropic_gravity