That’s just the nature of it, but it can still manifest itself in a (somewhat) external way – it just stems from an internal problem.
I had a character that was a complete and total fraud, she was a ‘chameleon’ (manipulation). She would disguise her house to pass as different people, and would adapt and change herself to suit the situation. You could argue they were ‘do-er’ actions, but I think they were just external representations of a ‘Playing a Role’ Be-er concern.
The emphasis (as I understand it) isn’t on the actual things that the MC does, but the internal purpose and problem – that’s what the MC throughline is about. The Be-er/Do-er thing is just clarification on their preferred ways.