How to fix screen tearing and flickering in Assassin's Creed Valhalla?

While exploring the wilderness, character edges showed weird flickering and jaggies that were distracting at 4K. I tried switching DLSS to Balanced mode; while I gained 10 FPS, the image became blurrier, which was the wrong direction. I used the GamePP Image Sampling Calibrator to raise sharpening from 40% to 68% and locked the rendering scale at 100%. RivaTuner confirmed the reduction of jagged edges, and AIDA64 showed CPU temps stabilized at 64-70℃.