The engines internal physics sim uses the same functions/systems you are using ultimately, but ofc it’s designed for game-level simulations nothing crazy complex.
The Chaos physics engine is still relatively young and still measurably slower than it’s PhysX counterpart too. Newer versions of PhysX are likely orders of magnitude faster again, but last I checked NVidia sadly have no plans to maintain a PhysX branch of the engine as according to them, Epic’s abstraction API doesn’t make it easy. You might be able to find a PhysX branch on github somewhere though.
You could try experimenting with an earlier version of UE, but do keep in mind the engine is designed for game physics not extremely complex simulations. You might even have luck with Niagara since it’s a very highly programmable GPU solution, but that would take a fair bit of work ofc 