Actually, Chaos isn’t performing horribly like it did.
What does perform horribly is the rendering engine.
You’d think I had ray trace on or something given it drops down to 10fps with 1500 simulating engine cubes.
Removing the shadow casting off directional light allows to bench just the engine on ragdolls and boxes.
As far as stacking boxes, it works with default engine cube and no VR - could it be the template that’s bad?