As others have said, COVID is endemic like the flu. I am older so I get the flu shot every year and will probably get a COVID booster every year. As they say, these do not necessarily prevent you from getting sick however they significantly lower the probability of severe illness and death.
I also wear an N95 mask in crowded situations. I will definitely wear it in airports. On ships I will take the stairs when possible.
I think an N95 mask DOES help, some. Any other type of mask is probably useless.
Given how cruises operate these days there is almost a 100% probability of coming in contact with someone who has COVID. Everyone needs to look at their own risk profile (age, health issues, family history with COVID [if someone in my family died of COVID I would NOT cruise]) and make a decision as to what risk to accept.