Nah, he's a lot better than Barthez. I don't think Barthez could even kick it long. And he was tiny too. And more erratic. That being said, Onana has not been good enough since he arrived. A decent start to this season but he's making too many mistakes again. Obviously not helped by the constant changing in the backline, which is the one part of the team I'd prefer Amorim not to rotate so much.
Whilst I don't think he's good enough, I think one decent player in any position in this team will not look a decent player. The team is too mentally frail, too physically weak, just so many issues.