Types of ships

Whats the best type of ship

depends on your play style

if you want to deal damage use a destroyer
If you want to be tanky use a battleship
If you want the best of both worlds just use a cruiser and if you want to play safe and do almost nothing use an Aircraft Carrier

Take a look at their stats and their active abilities and decide it for yourself.
But if you need something truly op with almost no drawbacks, go for something like the Graf Spee, Kaga etc., they are pretty broken, at least in WoWs Blitz.

CV is actually fun to play, its not useless. When you get to tier 7 enem CV in random battles is just annoying.