I'm getting nasty screen tearing and visual breaks during fast attacks in Phantom Blade Zero beta. Why does this keep happening?

Whenever I chain fast attacks, these weird jagged tears appear at the screen edges, which completely kills the flow of a high-speed action game. I dug into the logs and saw the VRAM clock on my Sapphire RX 7800 XT 16G was jumping wildly between 2000-2200MHz, causing frame times to swing from 12-30ms. I tried enabling Enhanced Sync in the driver panel first, but that was a total waste of time—it didn't fix the tearing and just added about 15ms of input lag. I finally decided to manually lock the VRAM frequency at 2100MHz and tweaked the core voltage to 1.10V. Using HWiNFO, I saw VRAM usage stabilize between 8.2-10.5GB, and the frame time graph finally flattened out. I did hit a snag where the screen flickered black during the first lock, but dropping the offset by 25MHz fixed it. Core temps stayed around 64-69℃ with fans humming at 1500-1700 RPM. After running a few benchmarks, the rendering glitches are gone, and frame times are rock steady at 5.1-6.4ms.