Self-adhesive vinyl on screed

We want to equip the rooms + hallway in the attic with click vinyl as well. We would like to use this product: planeo Rigid Klick-Vinyl Eiche Natur waterproof & dimensionally stable RIGID carrier board

Does anyone have experience with this? I have samples with this rigid board and without. With rigid, I cannot bend the sample. With the "normal" version, I can bend it relatively easily.

We want to lay it on the screed and possibly place an impact sound insulation mat in between. Is this recommended? I think impact sound insulation is basically always good, right?

I find it more comfortable to walk on vinyl than on tiles! It is simply "softer," but more "in the joints" or when sitting on it, rather than sinking in when walking. We have click vinyl in the apartment. What it will be in the house is not yet decided. The only thing that really bothers us is that you quickly have to wipe up if something drips, spills, or the watering can overflows, because you don't want it to run into the grooves =/

@ "JaAberNein":
Pure confusion after these hints?
The following:
No screed can be made so flat, not even flowing screed, that it meets the high requirements for flatness for LVTs! A pourable leveling compound, let's call it that, has two tasks:
1. to create the suitable flatness and
2. to ensure uniform absorbency for bonding.
Now you want to install self-adhesive LVT, which is not provided with tongue and groove.
These elements are usually only 2mm thick and take everything badly that is not "planar flat".
Yesterday I checked such a surface in the Ruhr area, where a strip of leveling compound only about 0.2mm thick (probably accidentally got there) on the surface of the covering caused unrest with the client. Applying such a leveling compound without any trowel marks (these are semi-circular contours visible in backlight) is a craft art!
Therefore, today it is no longer spatula-applied, but trowelled and then de-aerated with a spiked roller.
So it is not so simple with the leveling compound!
Further, it must be considered that you have underfloor heating.
Dry adhesives have the property that their adhesive strength decreases significantly (!) under heat influence. And PVC planks will undoubtedly expand under these circumstances.
The forces exerted by the planks can no way be absorbed by the dry adhesive. Just take a look at the product data sheet of LVTs for the term "suitable for underfloor heating". You will probably not find this for the aforementioned reasons.
Smooth the screed surface with a pourable compound using the trowel method and then glue the planks with a wet bed adhesive.
That way you will have peace! Otherwise, there will be less pleasant events on and with the floor.
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Regards and a safe decision: KlaRa