Could be that the video codecs are having a harder time compressing your game. It might be worth checking if alternative streaming software like Virtual Desktop and SteamLink have the same effect.
The ASW equivalent Motion Smoothing in SteamVR doesn’t use the depth buffer to extrapolate the frames, only motion vectors. Meta’s ASW 2.0 is generally regarded being better than Valves Motion Smoothing, so if the wobble is worse with Link when not making the framerate, it could indicate incorrect depth buffers being submitted.