I think you should call Carnival and confirm, and the community members here would just have anecdotal evidence.
I have read they are trying to roll out a testing program at the port, which would cost around $10. I think the program should be in effect by the time your cruise. https://www.cruisehive.com/carnival-cruise-line-embarkation-updates-protocols-to-remain/64407
Please consider getting vaccinated if you and your family are able to.