Does Allah's saying, "So woe to those who pray, those who are unmindful of their prayer," apply to whoever delays prayer until half an hour before Isha due to a study circle?

Those whom Allah has threatened with woe in His Almighty words: (So woe to those who pray, [But] who are heedless of their prayer) are those who delay the prayer until its time expires, not those who delay it from the beginning of its time.

Nevertheless, it is advisable to perform the prayer at the beginning of its time if possible. If it is not possible due to an excuse, such as the need to study, then there is no harm in delaying it from the beginning of its time. It should also be known that congregational prayer is obligatory unless there is an excuse.