I think alt-right is a pretty useless and outdated term, and I whenever I hear it I usually assume the person using it must've not paid attention to politics after the last election cycle. But there is a small sliver of truth that the American right has a militant wing and a political wing, with the militant wing having merged existing elements of white supremacist gangs and police (but I repeat myself) with newly radicalized boogaloo boys, proud boys, groypers, atomwaffen, etc. The political wing maintains loose coupling with the militant wing (and of course, the FBI manipulates individual groups to hit targets they desire) to keep plausible deniability.