In US they are mostly from Kabul or Northern Afghanistan, very few Pukhtoons from outside Kabul. They are mostly secular, drink beer, eat pork, party in night clubs,, and marry Non-Muslims. Very few go to masajid. They are same like Iranians here.
I once went in Tabligh and met one Parsiwan Afghan, he was learning Islam mainly from Indians. Funny thing is that we were both wearing the same style red cap when we met, so I thought he was Pakistani initially.
A met a few foreign students from Afghanistan who came to our masjid once, I showed them around town. They were Pukhto speaking. That was the only time I remember seeing religious Afghans in the US.