Is there a greater reward for praying with a larger congregation than with a smaller one, and what are the benefits of praying with a large congregation?

Yes, the reward for supererogatory and obligatory prayers increases with the number of worshippers. The prayer of a man with another man is purer than his prayer alone, and with two men it is purer than his prayer with one man. The more numerous they are, the more beloved it is to Allah. It is preferable to pray in the mosque that gathers the largest number of worshippers. As for the saying of some scholars that the virtue of congregations is equal, based on the hadith (definition) "Congregational prayer is twenty-seven degrees better than individual prayer," this has been refuted by stating that this multiplication of reward is attained by the minimum number for a congregation, and this does not prevent the increase of reward due to the large number of the congregation or other reasons.