My Frankenstereo has assorted grounding elements behind the rack. The head end of the streaming chain is in another room. At the wall outlet, there’s Nordost QBase 4 Mk II – with a ground lug.
I tried this inexpensive grounding tweak clipped on to the lug. Subtle – but it works. More transparency. Probably similar results with the Puritan Ground Master – and other brands. Worth a try! Certainly more affordable than an Entreq. I purchased the cheapest one with the copper wire/paper cylinder. (Not a fan of silver-plated wire.)
YMMV