This was Etihad's Lounge when it was first built in 2016 however Etihad sold their MEL and SYD Lounges to UK's No1 Lounges a few years later when EY was bad financial trouble and rebranding them The House Lounge - The Reason for Etihad Branding still being affixed to the front entrance is its very difficult to remove!
I agree that the American Express lounge is underwhelming. For a high end premium product it should be better. Didn't have the chance to check out Plaza Premium either, agreed that the House is a great lounge! Thanks for posting.