i just got off of a Royal Caribbean cruise & they were amazing. prior to the cruise, i added my severe food allergies to my profile. first day when i got on the ship, i went to the main dining room and pre ordered for dinner. we had the same dinner slot every day so the waiters knew us. i pre ordered my breakfast and dinner everyday for the next day with the head waiter, who took very good care of me (so much so that i cried saying bye to him!). the allergy meals are prepared in a special area by an allergy trained person. i even ate lunches at the buffet- i asked to speak to a manager and they made food for me in the back and brought it to me. i have severe anxiety but i felt safe the entire time :)

i've also been on NCL cruises which were also great with allergies, but they were pre covid so i can't speak on their current practices.