Is it permissible to combine the Dhuhr and Asr prayers by advancing them, and to combine the Maghrib and Isha prayers by delaying them, when it is difficult to perform them at their prescribed times due to work circumstances, and does the one who does so receive the reward of congregational prayer?

Please refer to Fatwa (definition) No. 31128 to learn about the ruling on combining prayers due to an excuse. And whoever prays alone due to an overwhelming excuse that prevents him from praying in congregation will receive the reward of praying in congregation. The proof for this is the hadith (definition) of the Prophet, peace and blessings be upon him: "If a servant falls ill or travels, what he used to do when he was healthy and resident will be written for him."