Is taking the distance of qasr (shortening prayers) based on the hadith mentioned in Sahih Muslim regarding a distance of three farasikh (20 km) the correct approach, and is forsaking the opinion of the majority, who hold a different distance, considered abandoning the Sunnah?

The hadith the questioner referred to from Imam Muslim concerning the shortening of prayer is authentic. Many scholars interpret it to mean that the Prophet, peace and blessings be upon him, used to shorten his prayers after traveling three miles or more.

The majority of jurists hold that the command for a sutrah (barrier) in prayer is for recommendation, not obligation.

A Muslim must follow what is authentically reported from the Prophet, peace and blessings be upon him. A scholar who wishes to act upon a hadith must verify its authenticity, ensure it is not abrogated, and confirm that there is nothing that restricts or particularizes it. The Imams and scholars have already carried out this work, so those who follow them should not be accused of abandoning the Sunnah.

Shaving the beard or trimming it to the extent of disfiguring it is considered fisq (transgression).

Using an alarm clock is obligatory for one who does not wake up for prayer.

There is no objection to seeking a fatwa from a scholar, provided their answers are presented to other knowledgeable scholars. What is correct from these answers should be adopted, and what is not should be left, while courteously pointing out the correct view to the scholar and their students without disparagement.