If it's before summer season then I only like Miami area beaches... Not sure if you would consider anything there a hidden gem but you could do mid beach instead of south beach for a more chill environment. Miami area has best weather and warmest water before summer season. During peak summer... I don't know I haven't traveled enough.
"Looking for hidden gem beaches along the continental US or just a short flight away? Have you ever explored the lesser-known coastal treasures? Share your favorite hidden gem beach destinations with us! #asknostr ποΈ"