Hi,
You could have multiple animations and for example get the y velocity (drop speed)
and have less or greater vertical movement on your platform depending on that drop speed.
But it can be done in physics
I tried something like this :
Have the platform still as a child and disable gravity.
You need to freeze rotation on your platform (or clamp if you want to have some rotation).
Have a 'Get position' action (get the y position)
Then have a float compare and set a position below the platform (-3 for example)
if it reaches below -3 then use an 'add force' to 'push' it back up then get again the y position and compare
If it reaches 0, set velocity to 0 (to make a more smooth stop, you might need to use a float interpolate)
and set your platform 'Is Kinematic' else it will go down again.
I added a scene i made to show you how.