Is delaying prayer for an hour or less after the Dhuhr call to prayer in order to finish a lecture and then pray in congregation considered a dereliction of duty and falling under Allah Almighty’s saying: "those who are heedless of their prayers"?

The Sunnah is to perform the Dhuhr prayer at the beginning of its time, based on the Prophet's (PBUH) saying: "Prayer is for its appointed time." Delaying it for the duration of purification, performing the Sunnah prayer, and a short wait for other worshippers does not take the prayer out of its early time. As for a long delay, Muslim women are advised to pray at the beginning of the time and then continue learning the Quran. This delay does not make them among those included in the verse, "Woe to those who pray those who are heedless of their prayer," because the heedlessness intended here is delaying the prayer until its time expires. The most that happens to these women is missing the virtue of praying at the beginning of the time, and they can be advised. Otherwise, learning the Quran should not be abandoned because of this, and you can pray individually at the beginning of the time.