Average between two Animation Layers

Hello Community,

how do I blend between two layers in such a way that the actual animated values take the average between the two animation clips?

What I want to achieve is that a specific animation looks more “professional” for a character that has a higher “skill” and looks janky at low skill.
For this I have created a professional and a janky animation clip of exactly the same length, then duplicated my animation layer, swapped the clips and set the weight of the layers depending on the skill (normalized, so that one of the layers is always at 100% weight).

The result is not as expected however. With the layers are in “override” mode only the lowest of the layers is used at all and in “additive” mode, it’s entire nonsense because I do not want to add values.

How comes there is no “blend” or “average” mode?
Am I looking at the wrong mechanism for this?

Huge thanks in advance!

A 1D Blend Tree would likely do a much better job than layers.