Is it permissible to combine the Dhuhr and Asr prayers by advancing the Asr prayer (taqdim), and the Maghrib and Isha prayers by delaying the Maghrib prayer (ta'khir), given the nature of night shifts that end in the morning, followed by sleep from after Dhuhr until the evening?

The fundamental principle is to perform the prayer at its appointed time. Delaying it is forbidden, based on the words of Allah the Almighty: (Indeed, prayer has been decreed upon the believers at specified times) and (Then, there succeeded them a posterity who neglected prayers and pursued desires; so they are going to meet evil). Combining two prayers is permissible for excuses such as travel, illness, or rain. Some scholars permitted it to alleviate hardship and difficulty, based on the hadith of Ibn Abbas: (The Messenger of Allah, peace and blessings be upon him, combined the Dhuhr and Asr prayers, and the Maghrib and Isha prayers, in Medina, without fear or rain, so as not to cause hardship to his Ummah). However, this should not be done habitually. Prayer is the most emphasized of obligations, therefore, it must be preserved, and affairs should be organized around it. Strive to perform the prayer at its appointed time. If sleep overcomes you, then you are excused. Do not resort to combining prayers except for a clear excuse such as illness, travel, or extreme fatigue that prevents its performance, and provided that it is rare.