What is the ruling on delaying prayers (Dhuhr, Asr, Maghrib) to perform them all together at night due to work circumstances, given that there is a nearby mosque and it is not permitted to leave during working hours except during the lunch break?

Delaying prayers until night and then praying them all together is a great reprehensible act and a grave sin. Work is not the reason; rather, it is laziness and negligence in prayer. Dhuhr, Asr, Maghrib, and Isha prayers can be performed at their appointed times, either in congregation at the workplace or individually. It is not difficult to find a short time to perform them. If great difficulty is encountered, one can combine the prayers. If work conflicts with prayer, then one must leave that work and search for another, and one must repent to Allah the Almighty.