Hi,
I agree dress code is a minefield...
There is an influencer called Gary Bembridge (Cruise critic, please delete if not allowed) who does brilliant youtube videos on Cruising and has a lot of tips re cruising. He has suggested that for men travelling on Cunard a tie/bow tie is a must on gala/formal nights, but open neck with sport jackets is acceptable on casual evenings
I am packing as a posh frock for each of the gala evenings