That is actually incorrect.
Irl warships goes as:
Corvette - smallest naval vessel that can be considered a “Warship”
Frigate - bigger than corvette, usually used to escort bigger ship
Destroyer - name derived from “torpedo boat destroyer”, during WW2 was used in escort role, modernly they are naval workhouses.
Cruiser - ship big enough to be capable of independent operations, usually used for recon, recon denias, and raiding. in some cases used as escort role when raiding was expected. Modernly only a few navies invest in those, because they are unnecesarily big targets for weaponry.
Battlecruisers/Battleships - the fun part in here is that the only battlecruisers in eve that are true to their irl name are assault battlecruiser - irl it was basically a battleship grade gun on a ship with a speed of the cruiser, essentially cruiser killers but were as expensive as battleship and treaties restricted both equally. During WW2 Battleships were “the” capital ship and battlecruisers and battleships evolved into shared type - fast battleship. and similary both were obsoleted by rise of carriers.
That being said I find it interesting that of all things it’s frigates that got your attention despite being quite accurate - while the game diverges greatly from your “typical” navies by labeling battlecruisers and battleships as sub-capitals, treading 2/3rd of battlecruisers as armoured cruisers (cruiser guns, less speed but better ability to tank hits) and the fact that for the purpose of “capital ships” they have taken what’s essentially a type of battleship, and made it into whole separated type from battleships.
Now I take it that the t2 names of some frigate types may seem confusing, since they’ve got airforce terms to name it.
For example if we wanted to put proper naval terms onto t2 frigs we would get something like Stealth Bombers being renamed into torpedo boats - because that’s precisely what they are. They are frigate sized ships armed with TORPEDOES that rely on not being detected before they can deliver their strike.
Assault Battlecruisers are proper equivalent of irl battlecruisers.
“Pocket Battleship” was an outside nickname for certain ship classes, and they were officially classified as “Armored Cruiser” or “Armored Ship” depending on how you translate.
The thing with black ops batleships is that 1) if there was equivalent in existance it would have been kept secret from the public due to the nature of the “black ops”, 2) hiding a battleship sized ship nowaday (prerequisite for well conducting operation you don’t want anyone to know it was You) is a tad difficult, and unfeasible irl. In-game you have cloacking devices and covops jump drive.