RDK (Russvolcorps) and a few other associated groups are known to be Neo-Nazis (sorry their names escape me right now). RDK’s philosophy is fighting for a smaller Russia just for ethnic Russians. The leader of RDK and other members have openly said they are Neo-Nazis. They are ethnonationalists. Also yes, they are paramilitary.

That image in the OP has the RDK flag.

This image is from their first incursion into Belgorod, the recent one wasn’t the first. The guy standing on the BMP has a small RDK flag, and you can see their armbands.

EDIT: I just realized the guy with the censored face in my photo is the same as the guy with the patches in the OP. Same body type, gear, and tattoo on arm.