None of these three explanations is considered plausible by modern scholarship.”
In early Vedic literature, Agni primarily means fire as a god reflecting the primal forces of consumption, transformation, and transmission. However, this term is also used to denote “Mahabhuta,” one of the five elements that early Vedic thinkers considered the constituents of material existence, which later Vedic thinkers such as Kanada and Kapila identified as Akasha (ether), Vayu (air), Apas (water), Prithvi (earth), and Agni (fire).
The word “Agni” is used in many contexts, ranging from the fire in the stomach, domestic fire, sacrificial fire on the altar, cremation fire, fire of rebirth, fire in the energetic juices hidden in plants, atmospheric fire in lightning, and celestial fire on the sun. At the level of the Brahmanas, for example, in section 5.2.3 of the Shatapatha Brahmana, Agni represents all gods, all concepts of spiritual energy that permeates everything in the universe. In the Upanishads and post-Vedic literature, Agni additionally became a metaphor for the immortal principle in a person, and any energy or knowledge that absorbs and dispels the state of darkness, transforms and gives rise to an enlightened state of existence.
Vedas
One of the sages in the Rigveda (Sukta IV.iii.11) states that the Sun became visible only when Agni was born. In the Vedic pantheon, Agni holds the highest position after Indra, the king of the gods. Agni holds a prominent place in the hymns of the Vedas and especially the Brahmanas. In the Rigveda, more than 200 hymns praise Agni. His names appear in almost a third of all 1028 hymns of the Rigveda. The Rigveda begins with a hymn invoking Agni, who is later addressed in the hymn as the guardian of Rita (Dharma).
In Vedic mythology, Agni is also portrayed as a mysterious figure with a tendency to play hide-and-seek not only with people but also with the gods. He hides in strange places, such as waters, where in one myth he fills the living beings dwelling in them with life force, and in another, where fish report his presence to the gods.” You see, it’s not for nothing that nowadays fire is so often connected with water. We will come back to this later.