What is the ruling on abandoning congregational prayer in a village where people are led by unqualified individuals who commit errors that invalidate the prayer, especially since there is only one mosque and an unreliable religious authority, and after attempts at offering advice?

It is not permissible to be led in prayer by someone who violates a pillar or a condition of prayer. If the imams are in this state and do not heed advice after all efforts have been made to advise them, you can pray in congregation at the mosque after their congregational prayer. If you fear discord, then pray in your homes in congregation, and continue to educate the imams until they abandon this violation. However, if the mispronunciation does not invalidate the prayer, then it is obligatory to attend the congregational prayer and follow them.