GOT IT!!
I knew it could be something simple! So this it’s my current solution:
I’ve made only one state change, to avoid transition state error at quick changing values. Now it goes from Idle to Steering for any values !=0, and goes back to Idle at any 0 value.
Then, inside the steering state, I’ve used a Blend pose by bool:
And that’s it! Now the Blend by bool is outputting the correct blend at any correct value, even when changing quickly from positive to negative, as soon as it stops steering, it simply goes back to Idle.