Personally I believe the council of Nicaea needs to be investigated simply because Constantine the Great had his hands in it to unite Christianity and pagans under his leadership. This lead to the murder of various groups under the name of stamping out heresy.
The first council of Nicaea happened late summer of the year 325. The divinity of Yahusha, called Jesus was in question. This council condemned Arianism. This lead to establishing the Nicene Creed.
"We believe in one God, the Father almighty, Maker of heaven and earth,
and of all things visible and invisible.
And in one Lord Jesus Christ, the Son of God, the only-begotten, begotten of the Father before all ages. Light of Light, true God of true God, begotten not made, of one essence with the Father by whom all things were made;
who for us men and for our salvation, came down from heaven, and was incarnate of the Holy Spirit and the Virgin Mary and became man. And He was crucified for us under Pontius Pilate, and suffered, and was buried.
And the third day He rose again, according to the Scriptures; and ascended into heaven, and sits at the right hand of the Father; and He shall come again with glory to judge the living and the dead; whose Kingdom shall have no end. And in the Holy Spirit."
The question is, what is Arianism? The view of Arianism is that Yahusha was created by Yahuah the Father as in at one time the son became into being. This would say that Yahusha is subordinate to the Father in nature, essence, and power. Also that Yahusha is not of the same substance, but of a similar substance. Arianism is said to reject the orthodox doctrine of the Trinity (Father, Son, and Holy Spirit as one God in three co-equal, co-eternal persons). Orthodox Christianity affirms Yahusha is fully God and fully man, while Arianism sees him as the highest created being, but not God.
Emperor Constantine wanted the Council of Nicaea to unify Christianity, addressing debates on Christ's divine nature (Christology) and church discipline including the creation of early canon laws, including setting the date for Easter.
Instead of pointing out the errors of both sides based on my opinion, here is my statement using quantum mechanics as an outline.
I asked Google AI a question. In quantum mechanics, can 1+1+1=1? This is in comparison with God the Father, the only begotten Son and Holy Spirit. The answer was Yes. It has something to do with angular momentum.
I'm not a scientist, I only search out information. Angular momentum tells us both the speed of the spin and how far the mass is from the center of that spin. The further away the mass is, the more angular momentum there is.
I asked a second question. Is there an Alpha and Omega in angular momentum? The answer is, Yes. Alpha is angular acceleration and Omega is angular velocity.
My third question was, can angular momentum have mass? The answer is yes. I quote, "In a rotating system, angular momentum is directly proportional to mass. If mass increases, angular momentum increases, assuming other factors are constant.
In other words, Yahusha is fully human and fully God. He was created from the Word of Yahuah Elohiym becoming flesh and then in resurrected glorified flesh. Yahusha is fully God because He is part of the Trinity before the SpaceTime continuum began. Then there is quantum entanglement. Yahusha is entangled with Yahuah Elohiym.
So I cannot fault the Niacin Creed. However Arianism should not have been condemned and called heresy. What Constantine the Great really did was mixed paganism with Christianity. By uniting Christianity he divided Christianity. The killing of Christians called heretics, he broke the Ten Commandments. For over a thousand years later, the Church was still killing Christians.
If it wasn't for Attila the Hun, the two Roman Empires, East and West, would still be going on. Rome had to abandon Britain and make treaty with the people they were fighting to confront the Hun.
Earlier Rome had flogged Queen Boudicca and confiscated her country. Her two daughters were gang-raped by Roman soldiers. After the Romans abandon London, it was wilderness until the Vikings arrived.
The council of Nicaea enacted several early church laws called cannons. They addressed such matters like clerical conduct, the ordination of bishops, and procedures for dealing with schisms. Latter they also mandated a uniform date for celebrating Easter. However these religious holidays are not correct. Christmas, called the birthday of Yahusha is not December 25th. He was born September 11th, 3 BCE.