Is it correct to repeat the Asr prayer with the congregation after having performed it by way of Jam' al-Taqdim (combining and advancing the prayers) during travel, just because the time for Asr began before reaching the intended destination, or was the Jam' al-Taqdim sufficient?

What was done by combining the Asr prayer with the Dhuhr prayer during travel is sufficient, and one is not required to repeat it, even if the traveler reaches his home country before the time for Asr begins. This is because the prayer was performed at its prescribed legal time. However, if it was prayed individually (not in congregation), it is desirable to repeat it with the congregation to gain its merit.