Insulating a concrete floor for engineered wood.

I am trying to workout how to insulate a concrete floor so that I can lay an engineered wood floor on top.

I’ve seen some “high insulation xps underlay options - https://www.irishflooring.ie/product/qep-xps-classic-5mm-high-insulation-wood-underlay-9-76sq-m/

But 5mm doesn’t sound like much? But I would worry about adding more as I assume it will squish over time, I need it to support couches, kitchen appliances, etc…

I could just put the engineered wood straight down on top of the concrete after a DPM but I would love to add as much insulation as I can get away with while I do this.

I know I should tear it up and install underfloor heating but this is out of my budget and time frame.

Any advice or experience here would be greatly appreciated. Thank you.