How can I speed up the animation of a given layer or current clip from the code?

I’m not interested in changing the overall speed of the animator.
I do not want to use the property of the animator, which changes the clip speed multiplier. I need to get direct access to the multiplier change.
I do not like the method using CrossFade with the transition to the end of the clip. It gives a blend, not an acceleration.
Using Legacy animation I almost got the desired result. But the animation component can not play multiple animations at the same time.

@Algok You can do this by adding a control track each for your solo or grouped items, adding a control playable asset to the track and then adding the assets as the source in the control playable asset (right side inspector). Now you can expand or compress the each item in each control track.