>I seriously wonder it it’s at all worth it to spend colossal sums on “stealth” ships? I know they can’t be made anywhere near as radar-invisible as stealth aircraft.
Given a submarine’s operating-profile IS stealth, and your argument/observation about aircraft being better suited for being nearly radar-invisible perhaps the answer is a submarine/aircraft-carrier. {I heard the Japanese had two at the close of WWII that we captured... and then blew up in war-games.}
Japs had kit-aircraft they assembled upon surfacing in their submarines: one such plane bombed an emplacement—in California!