I mean, just looking at the two, Hagel's shoulder is directly at Barkov's head when he makes his hit, and he puts a slight upwards trajectory into the contact. If he didn't actually hit the head it's very surprising.
Tkachuk isn't really close to Hagel, and realistically looks like he's intentionally staying low on the hit.
Neither of these violates Rule 48 if the puck was present, but given they both violate the interference rule I'm definitely factoring in that one of them was clearly more malicious than the other.