I also agree, and a tube on the inlet to straighten out the airflow is something I seriously considered.
But it works very well as is. Today I milled a wing from XPS foam (like here, with one wing half milled from 60x15x2 cm of foam). The leading edge was milled with a 0.1mm stepover, so it must have created tiny and very lightweight dust particles. And it all ended up in the bucket as far as I can tell!
Since it’s working so well I don’t feel very motivated to keep on tinkering with it. I just want to get some stuff milled with it now 