Decoupling piano from floor

Hoping someone here has been through the same! I've just gotten my first acoustic (Yamaha UX), though I played my digital loud (clp 825, max vol). To be comparable to my teachers acoustic. Now I've got the real deal, even though it isn't much louder thsn my digital, my neighbours get the full experience. Even with the practice pedal they hear bass all the way to treble.

I've sold a kidney* and am trading my UX up for a new K300 with Aures2. Considering I play 1-3 hours a day, I'll be doing all the learning an repetitive work silent, and keep about half an hour of acoustic work. The piano will be smaller, so less sound pressure. But I feel that the main culprit is our connected concrete flooring. We never really hear eachother, except contact noise.

So that got me looking into isolating the piano of the floor. Obviously the piattino caster cups look and seem great, but they're 205 euro for 4 cups. I could only sell 1 kidney*. There are cheaper options, like Jahn isofloor. Or Pisolo sound proofing castor cups. Or DIY with a sheet of sorbothane and some plastic cups. Anyone of you that has gone down that path and got someyhing to recommend?

*I'm joking, pls don't sell organs on the black market.