What is the ruling on disliking an Imam who prolongs the prayer and recites long surahs, and does the prayer become invalid by that or by being distracted in it?

If the Imam prolongs the prayer in a way that causes hardship to the congregants, he should be advised that the Sunnah is to lighten the prayer and to emulate the weakest among the people. As for his recitation of long surahs, there is no harm in it as long as it does not cause hardship to the congregants. The congregant, for their part, should strive to bring their heart to the prayer and reflect on the verses. The prayer is valid and does not need to be repeated.