vaguely resembles one used by a nazi division, that doesn’t appear to be very mainstream, even among neo Nazis

The SS Totenkopf was used the insignia of the SS deaths head units, the units that staffed the concentration camps. Every concentration guard had that exact totenkopf on their uniform in multiple places. Heinrich Himmler’s own fucking cap didn’t have SS bolts but the Totenkopf. It’s such a prominent SS symbol there was a tv sketch about this exact skull called “are we the baddies” that is now a pretty well-known meme.

“P-hustle” was also frequenting military history subs and even commented under a photo featuring the Totenkopf (albeit not prominently but in a comment chain pointing it out) https://undelete.pullpush.io/r/CombatFootage/comments/auy0bi/_/ehbh3n6/?context=4

I do not believe he didn’t know. This guy also came to the defense of people getting the SS bolts tattood. He got a covering tattoo when it became a political liability and not a second sooner.