most hacks used on 2b2t are things like velocity, elytrafly, freecam, etc. They dont really change the game its mostly just minor changes to vanilla features that make things easier

and yes i agree that a perfect anarchy server would be a server without hacks but sadly 2b2t is not perfect

entity speed is patched, jesus is patched, many many game-breaking things that make 2b2t not vanilla are patched, the ones that aren't are either because hause doesnt know how to patch or hes working on patching it.