Installing solid vinyl flooring on old cork flooring

I would like to install a solid click vinyl floor on an old, firmly glued cork floor. The height of the new floor would be 4 mm, so it doesn't build up too high. Now I have heard that you are supposed to install the vinyl floor with a thickness of 10 mm on an HDF board on cork floors because the cork is supposedly too soft. At least it absolutely doesn't feel like that: even if you press your finger very hard, nothing gives. What are your recommendations / experiences? Removing the old cork is not really an option.

About 5 years ago, we installed vinyl in solid material directly floating on our old cork floor (glued, about 5mm thick). So far, we have had absolutely no problems and the cork provides an additional nice impact sound insulation.

Hello questioner.
Installing a "PVC click vinyl floor" on an old cork top layer is certainly an unusual special construction. It should work because there is no rigid coupling (and thus no gluing) between the different types of flooring, and puncturing due to point loads (from the new PVC flooring) is also not to be feared due to the autonomy of its HDF carrier layer. Only the total construction height must be available so that doors do not scrape or a tripping edge to adjacent rooms is created.
Regards: KlaRa

Hello questioner. Laying a "PVC click vinyl floor" on an old cork top layer is certainly an unusual special construction. It should work because there is no rigid coupling (and thus no gluing) between the different types of coverings, and puncturing due to point loads (from the new PVC covering) is also not to be feared because of the autonomous HDF support layer. Only the total construction height must be available so that doors do not rub or a tripping edge to adjacent rooms is not created. Regards: KlaRa

Thank you for the feedback! But precisely because of the construction height, I would like to lay the massive thin vinyl floor without HDF. It is clear that the 10 mm thick floor with HDF should not be a problem, but this one builds up 6 mm too high for me. Does anyone else have experience with the 4 mm thick vinyl?