All the pit bulls I have seen were all short eared, short-muzzled and relatively small in stature. This doge appears to be long eared, long muzzled and of large stature. More like a kennel mixed breed. Not saying you are incorrect, just going by my general observation of the video footage.
He could be mixed, but just looking at him I’d say he definitely had PBT blood. His ears are not particularly long, they are the right set, and I don’t think he’s really large (hard to tell). The last is meaningless these days when people are talking about their 100-lb PBTs. There are many oversized 1s running around; not proper, but they’re there. Meanwhile, his head is the proper “apple” shape overall.