It is obvious and unavoidable that there must be a change.

The biggest problem with the proposal is there are two changes, not only the addition of a new button 1 but also a new action area different from the already established 1 and 2

What are effective ways to introduce this change without disrupting users' workflow?

Do not add more changes than those that are necessarily necessary

Personally

1. I would keep a single action area with the simple addition of the new function button
2. Color code keeping the same scheme for better identification of the new component

It is obvious and unavoidable that there must be a change.

The biggest problem with the proposal is there are two changes, not only the addition of a new button 1 but also a new action area different from the already established 1 and 2

What are effective ways to introduce this change without disrupting users' workflow?

Do not add more changes than those that are strictly necessary.

Personally

1. I would keep a single action area with the simple addition of the new function button
2. Color code keeping the same scheme for better identification of the new component