Huh, with modesetting driver, those patches eliminate the stutter when new windows are shown. Does the xf86-video-amdgpu driver need adjustments for this? However, turning on nightlight in Plasma Wayland still causes stutter, which is not there with amdgpu.dc=0. RedShift btw. is completely broken with amdgpu.dc=1 + modesetting DDX, it simply has no effect anymore (not related to the experimental atomic modesetting patches).