Mid-size resort with kids on nice beach?

I’ve done a ton of searching but am starting to feel like I’m looking for a unicorn. I want a short getaway to a beach next January with my two kids (age 18 and 12). Flying from DC.

I don’t want all-inclusive or a humongous, crowded, loud zoo. Looking for a medium-sized resort that has a decent pool for the kids, a calm beach (activities like paddle boarding a huge plus), and ideally restaurants close enough we can go off-property for some meals. Doesn’t have to feel luxury but we want to feel like we’re somewhere tropical (not at the holiday Inn down the street!) Willing to rent a car. Googling has been a nightmare as all I get are too luxury places costing over $1k a night or all-inclusive mega resorts.

Anyone have ideas for a great resort like this? Budget ideally under $700/night but willing to stretch that a little. Nonstop from DC is obviously ideal but willing to make one stop as well.