Welcome!
Are you referring to the beachfront filter, or the Beachfront Category?
As @Emiel1 said, there is not that much you can do to to influence which Categories Airbnb will put you in. You can add as many photos as you like as proof of a beachfront location, and write ”beachfront” and the distance to the beach everywhere in your listing. And you can contact Airbnb and ask why your next door neighbor is considered to be Beachfront, but not you, even if you are closer to the beach. And you can ask about the exact criteria for Beachfront (you will likely not get an answer…). You still might not make it into that Category.
Do I sound bitter? 😉 I speak from experience, but have given up. I don’t really think the Categories are used much when guests search, anyway, since they don’t work very well in searches.
Good luck with your hosting!