This was my thoughts. I will board outside the Schengen and only transit Europe.
An interesting read here https://www.theolivepress.es/spain-news/2024/02/01/will-a-cruise-holiday-in-europe-count-towards-my-90-day-schengen-limit-how-some-brits-are-avoiding-the-post-brexit-travel-rule-amid-utter-confusion-among-eu-and-uk-authorities/#:~:text=“As a general rule%2C calls,be registered by the authorities.”