These are not fit for combat. I served on the USS Coral Sea (CV-43) and it was armored. These littoral ships are thin-skilled and just about anything would punch a hole in it from one side to another.
Every ship in the US Navy has the same problem. And, just about all new ships everywhere.
Armor is out. Defensive weapons and Offense are in.
Why waste all that weight and bulk for armor when it can be used for missiles and radar?