Thick impact sound insulation, differences from thermal insulation

Hello everyone,
we will probably soon be owners of a solid house from 1900, without a basement, not insulated.

We want to lay laminate flooring in some rooms there. Now the question is which impact sound insulation and how thick it should be. There are various ones in the markets now, 2.2mm, 3mm, 5mm.

Are there big differences in the thickness of the insulation regarding thermal insulation?

Looking forward to your answers.
Thank you

Impact sound insulation primarily serves to reduce footstep noise, to compensate for minor substrate irregularities, and, if applicable, to seal against residual moisture from the screed. If no moisture protection is integrated, additional use of a foil is usually necessary. For significant thermal insulation, the thickness of the impact sound insulation is usually too low. In the case of underfloor heating, one must pay attention to a möglichst geringer Wärmedurchlasswiderstand, usually a very low thickness for the impact sound insulation is appropriate, e.g., up to a maximum of 2mm. Without underfloor heating, a greater thickness certainly contributes more to thermal insulation. Possibly, the compressive strength should also be considered to prevent the floor from sagging too much under load and effectively wobbling. It is best to consult a specialist again, to whom you communicate your floor construction and your requirements.