Do Vedas (and any other Vedic scripture, such as Puranas) hold any information on pyramids? What is their function? What can they do?
A Pyramid will have 5 faces.
The Vedic literature contains many hymns, describing spiritual aspects, in esoteric fashion. So if we consider those esoteric mentions, we can infer that a Pyramid is a an symbolic representation of panchabhutas or 5 elements.
Agni - Fire
Vayu/Indra - Air
Varuna - water
Earth - Aditi
Space/Heaven - Tvastr
Earth and Heaven are called the Parents of Gods in Rig Veda I.185.4
May we be close to both the Worlds who suffer no pain, Parents of Gods, who aid with favour, Both mid the Gods, with Day and Night alternate. Protect us, Heaven and Earth, from fearful danger.
The 5 faces of a pyramid represent 5 elements of Nature/God. That is why even the temple domes resemble, though not in exact manner, a pyramid.
The Meru Sri Yantra also resembles a pyramid.
Even a human sitting in a cross-legged fashion or in padmAsana, resembles a pyramid.
So pyramid is every where and in all times, only difference being in Egypt, the structures were constructed in exact pyramid shape.