Nia/Charlotte was probably the least good match. But it was a TV match in the middle of the show.
Fiend/Orton was not good, but it was just a match at WrestleMania.
Damien Priest/Miz was a corporate sponsor match that was designed to push a movie in a low-level feud. It did its job.
Bobby Lashley/Goldberg was not terrible at all.
Omega/Moxley was the Main Event of a PPV (Revolution not All Out) and was a dud (literally and figuratively).

The spot on the card and the type of card matters here, so I'm going with Omega/Moxley. It isn't all their fault but it was an embarrassing moment that ruined the entire show really.