I'm just gonna repeat what I said from a recent almost exact Hyperion thread. Its system needs to go, it's way too strong with 0 counterplay
Defending from Hyperion is quite similar to defending from phase frigates. Not impossible, just takes your full concentration on the task.
For omni shielded ships you either keep constant 360 or
keep shield down and raise it reactively as Hyperion picks the spot to attack you from. Shield will be up a bit before Hyperion materializes and shoots.
Front shielded ships have to group together back to back, no way to survive alone.
Some ship systems can counter too, like phase skimmer.
But while AI Hyperion can be caught and destroyed,
a perfectly piloted Hyperion is pretty much invulnerable as long as PPT/CR lasts. Timing window between sequential teleports is so small that beams often fail to register single tick even if you materialize right into them, while projectiles need to be right on top of Hyperion at exact moment it materializes to hit.