Is My Cracked GPU PCB Beyond Repair?

There is probably very little chance of a practical repair. A modern GPU board has many layers, and even a small crack can sever traces and power connections across several of them. Repairing that properly may require specialized microscopes, board-repair equipment, schematics, and advanced experience. In theory, a donor board could be used to transplant the GPU core and memory, but that would be an extremely difficult and expensive job.

The lighting turning on does not mean the card is electrically healthy. The fan controller, power-delivery circuitry, memory connections, or signal traces may all be affected by the crack. Since another GPU works in the same system, the damaged card is almost certainly the source of the problem.

A reputable board-level repair shop could inspect it and tell you whether the damage is localized, so getting a diagnostic quote is reasonable if you want closure. Just set a firm spending limit first, because if the PCB itself is fractured through multiple layers, the repair may cost more than the card is worth and may not be reliable.