Interestingly, I read or heard something that said that a fatal flaw in hypersonic in regards to naval combat was that hypersonic speeds create plasma and that the plasma made optical sensors and remote control useless. They need to slow down in order to hit naval vessels, which makes them vulnerable.

Interesting to think that aircraft rendered armor obsolete so ships stopped having appreciable armor. But if your threat is swarms of small drones then armor becomes a viable defense. Especially since the quantity of the drones is what makes them effective. If they have to build much heavier drones to punch through the armor that would significantly reduce the quantity that can be carried and increase the effectiveness of the other anti drone defenses.

I guess it's true that countries are always preparing for the last war they fought, not the next.

It's gotta be a nightmare on one of those drone carrier ships to be hit by an anti-ship missile or a drone and have thousands of lithium batteries strapped to high explosives light off.