I'd still look at Zyon Maiu'u as that impact middle.
Pick him up, he offers versatility between middle & the edge, runs hard & has that 'impact' in his style- he's not a plodder, he's more a Royce Hunt type.
Thing is- you play him in KOE. If it doesn't work out- you don't lose much. But if he starts to crank it up in the KOE, then Royce's number starts to get looked at.
Given the Dogs are moving him on for whatever reason- I doubt anyone is paying full freight to take him. Cheap low risk addition with potential to be a massive upgrade. If he's your #30, you're doing ok.