How to get smooth pitch transition?

I’m having trouble with the howling system, because it can’t howl correctly.

I have 6 triggers, each trigger changes the variable ‘number’ when you press a number from 1 to 6 or you put the cursor over them.

Then, I have a timeline, lerp and ‘set pitch multiplier’ to a sound file.

And here’s the timeline: Screenshot by Lightshot

Any way to make the transition between pitches smooth?

I also have a video where I show what I want (Minute 0:50):