Not OC
What about the heat buildup of absorbing or even just deflecting the Death Star? That weapon destroys an entire planet. Whatever the Borg Cube uses, it would build up absurd amounts of heat going against the Death Star.
Tangentially related: I love the concept of a ship or space superweapon that uses excess heat itself as an additional means of attack.
Something a ton of sci-fi ignores is that heat can’t dissapate in a vacuum the same way it does planetside. If you have to put it somewhere, and if we assume you’ve re-captured/reused as much as is reasonable… then you could fire/railgun superheated stuff at the enemy. Literally make your excess heat someone else’s problem. Either hardened solid slugs to penetrate with the heat assistance, or materials engineered to “splash” and glom on on impact like ship sized space napalm.
Battletech has flamers, which are basically like if you took one of those WWII flamethrower tanks and powered it with nuclear fusion instead of napalm. The lack of a WarShip-class flamer for space combat seems like an oversight, though…