How does wood hardness affect the sound of a TT on a wood TT platform?

LIGO mirror suspended by glass threads video,

https://www.ligo.caltech.edu/LA/video/ligo20170216v

The wood in a plinth of turntables has much more influence for example than the wood used for making table tennis rackets.
Have you ever tried to use table tennis rackets with identical rubber but different woods?

I have been trying for a long time and there are macroscopic differences.
I believe that for the plinths the same thing is the same, the problem is that nobody has ever built plinths with different woods and then made tests and measurements with laboratory instruments.

So few of the geniuses above provide any practical, REAL, scientific insight into what Janka Scale hardness might be best for TT isolation.  Why don't you just say you're not certain rather than bloviating about what might work?

What is a fundamental to what is desirable as an inherent property for a Plinth or Isolation Platform - Sub Plinth for materials selected is the following:

Damping Factor ( The materials ability to harness received energy or at the other end of the scale bounce it back to the source. Preferably a High Damping Coefficient for an Audio Support ancillary used within a System).

Dissipation Factor (Speed at which energy within the material is lost or no longer significant as a reading)

Most who have a HiFi System and have the opportunity to make change, seemingly reject the materials available today that are much more fit for purpose to perform a particular role and maintain materials that are very poor and wanting for the role selected.

Do a search on “damping factor wood types”, there are some studies on the subject.