Hinduism has two types of God which is unique among world religions. Even many Hindus also do not know it.
(a) Saguna Brahman, God with Guna/attributes manifested, typically known as Isvara, the creator personal God.
(b) Nirguna Brahman, God without Guna/attributes, typically known as Para-Brahman or Sachidananda or impersonal God. The Guna or quality is unmanifested, a Niskriya perception.
Based on this, Hinduism has three major doctrines -
(a) Dvaita doctrine by Madvacharya [13th century] considers Saguna Brahman as highest reality. God is never Nirguna or quality-less. Jiva is eternally 'different' from God like child is different from parents.
(b) Visistadvaita doctrine by Ramanujacharya[10th century] considers Saguna Brahman as highest reality. Here Nirguna means God without any bad attributes, but with all good attributes. Jiva is a 'part' of God like hand is a part of body.
(c) Advaita doctrine by Shankaracharya[8th century] considers Nirguna Brahman as highest reality. Brahman without attributes is the true essence of this manifested creation. This manifestation is temporary and transient; so Mithya/False. Jiva is 'same' as God in essence. Vedic Mahavakya like Aham Brahmasmi, Tattvamasi refer to oneness of Jiva with Brahman. Please note, Jiva is same as Nirguna Brahman, not Saguna Brahman as Jiva already appears to be Saguna due ignorance.
Seeker begins with Dvaita. Then on maturity appreciates Visistadvaita. Finally realizes Advaita as highest absolute reality. Though Advaita is the simplest doctrine, still it is not popular among general public. Human mind does not accept the truth as it is due to attachment and aversion. So let's start with Dvaita sadhana which purifies mind and makes us eligible for ultimate Advaita sadhana.