As revealed in scripture, and by the early church fathers explaining misunderstandings, God is one God, one substance, expressed in three, co-existing, co-eternal, co-equal persons.
You see that if people thought Jesus was an angel, that would interfere with their faith's ability to save them, justify them.
The Bible says, Listen Israel the Lord your God, the Lord is united. And Genesis open with plural, God, they created... ElohIM.
The Father and the Son are the same age, being above time, having created time as we know it. Isaiah 9:6 YLT.
The Spirit who never manifested like the Son, is a person, because scripture says He has a mind, will and emotions. We are created in His image and likeness.
From God comes living water, light, love. This they seem to have in common. A common substance and nature, the same mind, three minds. Perfect agreement.