Imo to use timelines its best to have it in a seperate actor instance so they can work together. Did a quick test (and accidentally made the entire thing) making a blueprint for the knob and another to spawn the knobs and manage them.
The knobs:
This is how I manage the knobs:
In this actor I have an int array (iUnlockCode) with the unlock positions used to compare.
Result:
With this I can set different unlock codes per instance including directly affecting the amount of knobs:
Hope it helps.