Was this the one the Romans dismantled and shipped to Rome for building materials?...............
Maybe. But Arabs and locals were apparently dismantling it just decades before archeologist showed up.
They dismantled lots of temples, tombs ... anything really ... too.
Djedfre died early and it wasn’t completed. According to Quirke, who bases his pharaoh list on surviving monuments rather than Manetho, Djedfre’s young son succeeded him, but in short order was replaced by Khafre.
AFAIK the youngster’s burial is unknown, as is the cause of death. Since the son and successor of Menkaure and grandson of Khafre is listed in Manetho as the first pharaoh of the 5th dynasty, and his burial monument is a mastaba (a reversion to a prior practice) and nowhere near Giza, there may have been a dynastic struggle, other intrigue, and/or some kind of black swan (invasion, uprising, plague).
time index 44:00