Why is "ellie animation" play slow even in wireframe mode?

I updated Blender to 3.0 and downloaded the demo file:“ellie animation.blend”. I played the animation, and I only get something like 6fps even in the wireframe mode. If I see the Task Manager, GPU usage is not 100% but the CPU is 100%. I have 12 CPU threads and they are all maxed up. Did I set something wrong, or does it really need that much CPU power to play wireframe animation of a single wireframe cartoon human character?

PS: It seems that if I play the animation as it is, I get 25fps. But if I click a pose in the Pose Library (e.g., Ellie full cheerful) and then play the animation, even though the animation seems the same as before, the frame rate becomes 5~6fps.

I can click the facial poses with no issue and the animation continues to play back at 20+fps while showing the new facial pose. If I click one of the whole-body poses, then yes it drops to 5-6fps here as well. But it doesn’t show most of the pose, I think because the actual keyframes in the animation override almost all the channels that are set by the pose. But with the pose set, now on every frame it’s having to do something like combine the new pose with the keyframed animation channels and that’s a lot more work for whatever reason.

But I’m not really an animation person so probably someone else will know more accurately what’s going on.

Alright, can I remove all poses that I have applied from thr asset library? I mean, other than keep pressing undo.