Is it permissible to call the 'Isha' (night prayer) adhan half an hour before its time in a lockdown situation, and then immediately perform the prayer, and what is the preferred time for the 'Isha' prayer to begin after the Maghrib (sunset prayer)?

The 'Isha prayer is not valid before the disappearance of the red twilight (shafaq al-ahmar). However, the Hanbalis permit combining the Maghrib and 'Isha prayers due to hardship and difficulty, such as fear for one's life or property. Based on this view, combining the two prayers is permissible in this situation given the dangers associated with performing the 'Isha prayer at its prescribed time.