What is the ruling on reciting the Qur’an very slowly while the listeners repeat "Allah" or "Allahu Akbar" after every verse or two, and what is the ruling on changing vocal tones during recitation, and does that contradict تدبر (contemplation) and the purpose of the Qur’an?

The reader of the Qur'an should recite it with tartil (measured, melodious recitation), sing it beautifully, and improve their voice, as there are texts that encourage this. However, exaggerating the melodious recitation to the point where it resembles the tunes of songs and entertainment, and the attendees exclaiming "Allah" or "Allahu Akbar" after every verse, is not from the guidance of the Salaf (pious predecessors) and is a reprehensible innovation. This is because Allah commanded listening and paying attention when the Qur'an is recited, so that its verses may be contemplated.