Is comparing Al-Hafiz Ibn Hajar and Sheikh Al-Sha'arawi in merit and knowledge, and preferring one over the other, considered a sin or presuming to speak for God?

There is no sin in preferring some scholars over others. This is not the prohibited presuming against Allah, which was mentioned in the hadith: "Who is it that presumes against Me that I will not forgive so-and-so? Indeed, I have forgiven so-and-so and invalidated your deeds." Scholars, both ancient and modern, have always preferred some scholars over others in terms of knowledge, precision, mastery, and piety. Therefore, there is no religious impediment to preferring some scholars over others, especially for a legitimate purpose, while saying: "I consider so-and-so to be such, and Allah is his reckoner, and I do not sanctify anyone before Allah." Imam Ibn Hajar is one of the great scholars of the Ummah, and mentioning his virtues does not diminish the status of others.