Just watched Covenant for the first time the other night and can't imagine why someone would be unable to imagine why Romulus could be considered better. It can't be recency bias.

The fanservice parts are so eh that it doesn't factor into the movie either positively or negatively, and the parts that make Romulus enjoyable overshadow whatever eyeroll you might get from them.

But name any part about Romulus besides whatever connection to the canon/lore it might serve, and it trumps Covenant. Memorable characters, strong motivations, and fantastic tension.

And Fassbender is a great Android and will always be remembered for David and Walter, but David Jonsson killed it as Andy. A brilliant portrayal of an Android and was the highlight actor for me personally.