you could always try blowing instead of sucking https://www.youtube.com/watch?v=Bnck7UBztOM
Robin Raydont buy badger unless you are going full into a rug spa. just learn to know which ones will take the extra vac time and charge for it. one reason we always do onsite quotes for rugs and upholstery
7kilos !!Was it used on a beach
Was it a gun tufted rug? If so the dust could be the latex drying out & breaking up as well as normal soiling. That would look like sand.