My Kioxia G4 1TB is overheating and causing lag in Civilization VII after a few hours of play. How do I fix this?

When you're in the middle of a massive turn calculation and the game just hitches for 0.6 seconds, it ruins the experience. The Kioxia G4 generates an insane amount of heat during high-frequency R/W, hitting 75-88℃ and triggering the internal throttle, which crashed my speeds from 10000MB/s to 1200MB/s. I tried adding a case fan, but it only dropped the temp by 4 degrees—hardly noticeable. I eventually swapped the stock cooler for a thick pure copper passive heatsink and optimized my airflow to a strict front-in, back-out setup. HWMonitor now shows peaks at 55-63℃, and the speed is rock steady. I actually had a disaster during the install where the thermal pad was too thick and slightly bent the drive; I had to swap to a 0.5mm pad to fix it. Fans are steady at 1200 RPM. After a 5-hour stress test, the throttling is gone, but the drive still runs warm.