1-If a believing human is required to continually worship and remember Allah on this earth, why were the angels created then? They were created for that purpose. They never face death, illnesses, natural disasters, etc.
Allah gave the Children of Adam freewill which angels do not possess. It is for this reason that their worship is at times more valuable than theirs. In the face of immense temptations of the world, desire, ego, and satan’s whispers, and as you said, all kinds of troubles, they patiently maintain worship and service to Allah. This causes human beings to ascend to their rightful positions as viceregents of Allah on earth, and Allah knows best.