Sounds like they need a good Penguin sailor to trim main!In the interview with Goodison he talked about how they feel there is so much better control of the main when you use a boom. He says that he is constantly asking for more buttons on his sail trim controller so he can try new adjustments. Another interesting point he made is how you can really change the tuning of the sails with just the mast rotation. It sounds like you could really sandbag it by just making some subtle changes in the mast rotation that may be hard to detect.
( https://yachtracing.life/the-yacht-racing-podcast-americas-cup-special-part-2-paul-goodison/ )
I think that AM still has a tremendous amount of room for improvements in their maneuvers. Even the broadcasters mention how they were not as polished on their turns and you could see them lose ground on every turn. I think they were way too conservative and losing speed and VMG. You can see them out making quicker turns and dropping the second foil much later.