At the level of the AEAT there are "courtesy days", for which the interested party indicates a period of 30 days during which they are not notified; but this only applies to notifications in the area of the AEAT. It is regulated by a specific rule (RD 1363/2010, of 29 October), and there is no equivalent to the rules of common administrative procedure of the Public Administrations.
Therefore, it is not possible to configure the grace days in e-NOTUM, because it is not regulated by law. In this sense, you can request the establishment of courtesy days at the level of a specific procedure by contacting the issuing body, if you consider it appropriate, which should collect your consent, and, in such case, refrain from practice the notification on the indicated days.