Try these, which are one of the dirty little secrets in audio. They work perfectly, won’t break the bank, and don’t soften the sound. I use them under all of my components.
https://www.supplyhouse.com/DiversiTech-MP-2E-EVA-Anti-Vibration-Pad-2-x-2-x-7-8
https://www.supplyhouse.com/DiversiTech-MP-2E-EVA-Anti-Vibration-Pad-2-x-2-x-7-8