Could this be asbestos?

Hello everyone,
the following pictures show a layer of adhesive under a carpet and PVC flooring that was discovered in our renovation project.
Of course, we will have samples examined in a laboratory.
Nevertheless, I would like to ask about your experience with asbestos and such adhesives... Does it look like that to you? The consistency is extremely hard and brittle.

Thank you very much for your support!

I recognize the pictograms "sofa" and "bed" – so we are apparently looking at the back of a carpet recommended for living and bedrooms (I cannot interpret the other pictograms). This carpet was evidently glued down with a full-surface liquid adhesive. Carpet backings contain plastics (foam plastics), whose plasticizers naturally change over time. I do not know of any rollable material containing asbestos; it consists of fibers that, apart from being significantly smaller, can be imagined like those of chipboards. Exposing asbestos on such a large scale without respiratory protection, you would not be able to endure it for several minutes without developing a noticeable feeling of dust in the lungs.

Heat gun, melting the adhesive, spatula for scraping, all with the window open

Heat gun, melting the glue,

I am not sure whether this is a good DIY tip or perhaps an instruction for "smoldering fire homemade" (?)

Using hot air at 200 degrees would be safer for me than sanding,
even respirator masks with a 10µ filter area let everything smaller through

Thank you very much for your answers! The black turned out to be mastic asphalt (asphalt screed). I forgot to mention that we want to remove the screed in order to install underfloor heating afterwards. Now to a new building material: The brown is fibrous and seems to be an insulating material, whereas I assess the thin gray layer as asbestos cardboard. What do you think?