How to fix slow turn transitions in Civilization VII late game?

Around turn 200, clicking 'End Turn' resulted in a black screen for ten seconds, testing my patience to the limit. I tried disabling C-States in the BIOS, but the CPU temperature spiked to 92℃ per HWiNFO, making it an impossible solution. I used the GamePP Power Plan Switcher to set the mode to Extreme Performance. CPU frequency stabilized at 3.8-4.1GHz per HWiNFO, and turn transitions dropped from 15s to 6s per RTSS.