Minigolf isn’t turn based. Unreal’s physics system is fine, it’s just the way they step through the simulation that is not fine.
We’ve already got a fix for the frame rate issue. Redoing the physics is not the solution. Unreal uses frame dependent stepping for its physics. We’re switching it for Minigolf to fixed time step. We haven’t implemented it yet because we’re still testing it as it’s a massive change. It’s not a thing you can solve in a couple hours, no.