not much in the way of hardware physx being using anymore in modern games
That is correct.
NVIDIA is solely focused on RTX now, and since it is very demanding, not much room is left for hardware PhysX (I guess). Same goes for FLEX as well.
In general, PhysX SDK and FLEX development has shifted to enterprise market (robotics, simulations, etc).
Other gameworks libraries (hairworks, flow, etc) are used sporadically, but nothing breathtaking.
As Metro: Exodus, advanced physx option looks like a leftover there, I haven't noticed many additional effects except from some sparks.