You usually use the Present Perfect Simple tense for situations that describe the result of an action. If you want to focus on the action itself, you use the Present Perfect Continuous tense. cf.
I have been making cookies since before 5 o'clock.
I have made over 50 cookies so far. (the result of making cookies is the amount of over 50 of them)
She has been writing an essay for two hours.
She has written 2 pages up till now.
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