FWIW the answer (as far as it goes) is tucked away on the Blue Origin website and was a phrase used pretty much verbatim by the official commentator on the day..
“ The bottom of the capsule has a retro-thrust system that expels a pillow of air so the capsule lands at just 1.6 km/h (1 mph) ”…
so unlike Soyuz it’s not a pyrotechnic system, which would explain the lack of flames, smoke, and relative lack of dust.