Is it better to pray in a mosque with few worshippers, or in another mosque where the congregational prayer is held, especially if the time for the Adhan has passed?

If the mosque does not open except with your presence, and you will pray there in congregation, then your prayer in it is better than praying in another mosque, in order to attain the reward of maintaining the mosque and praying in congregation within it. However, if you will pray there alone, then praying in the other mosque where congregational prayer is established is better.