The most ancient nations had different Deities – sun, earth, fire, water. Next come the monotheistic ideas – belief in one god.
Hinduism since pre-historic times termed as Sanatan Dharma, believe in one “universal Brahman” i.e. Sat-Chit-Anand. Vedantic philosophy holds Brahman as creator of universe who as God created Jivatman (Souls) and physical world (Prakrati). Hence, Hindus believe in one supreme God (Mundaka Upanishad 2.2.11; Isha Upanishad, stanzas 4-8; Katha Upanishad, Brahma Samhita 5.1 etc).
Modern science has proved the matter in the world is composed of atoms which are made of proton, neutron, electron & other sub-particles. These particles are having energy and wave functions. The laws of conservation of energy and conservation of (total) mass are equivalent and both hold true. In physics, mass–energy equivalence states that anything having mass has an equivalent amount of energy and vice versa, with these fundamental quantities directly relating to one another by Albert Einstein's famous formula : E=mc2.
In Hinduism, Vedanta holds the view that Brahman is Cosmic consciousness (Sat-Chit-Ananda – Truth-Consciousness-Bliss) who creates universe – jivatma & physical universe, maintains and withdraws within it. Hence, Hinduism is more scientific.
Hinduism recognised various needs and desires of human being and to fulfil them various deities & forms are invoked. Though supreme God is nirakar (formless), it manifest in many forms to fulfil the needs. As electricity takes various forms to fulfil needs of light, heat, mechanical energy etc, Nirakar God take various Sakar forms in Hinduism without losing its eternal purity & characteristics of omnipresence, omniscience, omnipotent etc.
Of course, it is a better idea to have personal god though the Brahman is one supreme God, the creator of universe. Human mental frame feel more attached to sakar form of God.
Though all religions are essentially the same, they must have the varieties of forms produced by dissimilar circumstances among different nations.
There is no religion that is more aware of the transcendent, timeless, formless, causeless Truth.
The concepts of Vedanta on god, relationship of Brahman, soul & prakriti (matter) and multiplicity of deities in Hinduism creation, are discussed hereunder.