Hi Feras,
Thanks for raising your concern.
Could you confirm if your goal is to create a script that will only check whether specific label is already existing in your account? If yes, you may try to implement the sample script in this link as it will only retrieve the labels that satisfied the condition set on the label selector. You may also try to utilize the totalNumEntities() method as it will return the total number of labels that satisfies the filter set on the selector.
Let me know if you have questions/clarifications.
Regards,
Ejay
Google Ads Scripts Team