If this issue only occurs with 6.12.x, but not with 6.11.9, it might be related to Wrong frame timing/jerkiness with 120Hz display on 6.12 (bisected) (#3742) · Issues · drm / amd · GitLab
tl;dr: You can try to use kernel cmdline amdgpu.dcdebugmask=0x10 as a workaround until the issue is fixed.