I honestly can't see how he is overrated.
He isn't in the top tier fullbacks- Tedesco, RTS, Turbo, Slater before he retired, Ponga straddles the line of that club repeatedly. Gutherson isn't at that level, but also no one says he is. He seems appropriately rated imo. Even hardcore parra fans describe him as more reliable than superstar.
Even a few years back when he asked for 'big money', he wasnt really asking for much. There was a shortage of quality fullbacks so his market value would have been inflated, but even then It was reported he was only after $700k.