Is a father's anger at his son considered acceptable and effective with Allah if its cause is the father's rejection of the son's raising of his garment above the ankles (tashmir al-izar), performing congregational prayer in the mosque at dawn, and growing a beard, due to these actions being considered suspicious and confrontational to oppression? And what is the ruling of Sharia on this?

Filial piety is among the greatest acts of obedience. The prohibition of isbal (letting one's garment hang below the ankles) for pride or otherwise is the more preponderant opinion. Congregational prayer in the mosque is obligatory for anyone who is able, and there is no obedience to a creature in disobedience to the Creator. Therefore, do not obey your father if he prevents you from it. Shaving the beard is forbidden, but it is permissible to trim what exceeds a fistful. A Muslim must adhere to their obligations, except in cases of necessity that permit the forbidden. Necessity is estimated according to its extent, and it is defined as a person reaching a point where, if they do not partake of the forbidden, they would perish or be close to perishing, as stated in the Almighty's words: "But whoever is forced, neither desiring [it] nor transgressing, there is no sin upon him." This matter is left to your own assessment of your situation and circumstances to determine the extent of the necessity.