A method that has proven extremely well for myself, but always on Concrete Floors, that is ubiquitous in how all Audio Devices seemingly benefit, has been to build a substantial Plinth to build the Rack Upon.
The next substantial improvement where Vinyl as a Source is concerned is to Brace the Racks to become extremely rigid.
I can't vouch for the Braced Rack for a Digital Source, as many years past, I transferred these devices to a Industrial Type Gallows Bracket, which is Wall Mounted, to create a Shelf System.
The Brackets have a absorbent decoupling material between them and the Wall. The Shelves are Isolated from the Bracket Support and Audio Devices are Isolated from the Shelves.
This method works exceptionally well for the Digital Source and saved me having to expand on the footprint taken up of the Plinth and Rack below.
I have become an advocate of Solid Tech Feet of Silence Type Footers.
I an not familiar with the New Type where the suspension is Horizontally Orientated, but the good news is version of this type are available from other suppliers at a much more affordable cost.
Solid Tech also supply Rack Systems that utilise their suspension methods to separate the Tiers.