The idea of the Trinity did not make sense to me the first time I read about it, about 50 years ago. The dogma was the trinity and eventually, I just stopped fighting the idea. There is no Trinity in Islam. There is only one God. Most people are content to just follow their pastor because they think he will take the blame for doctrinal errors. In my opinion that's lazy. In the NT they are admonished to be like the Bereans, studying the scriptures daily. I'm alone, no reason to trust anyone but God.
Theoretically, a complete concept of God would need to include everything, since God is omniscience and omnipresent. This is conceptually beyond the human mind to comprehend and put into words, except as an intuition. Personification of God, is therefore more of a projection, based on a human subset, of what a complete concept of God is.
Concepts like the trinity break down the infinity, that is God, into three bite size pieces, based on how the majority of people worship and project.
As an analogy, Joe is a son to his parents, a husband to his wife, and a father to his children. He is respectful of his parents, loving and loyal to his wife, and firm but fair to his children. His parents interact in one way with him; nostalgia, his wife who is intimate with him interacts differently, while his children know him and interact with him in a third way.
Joe is one person but has three hats. The hat he uses depends on who is interacting with. This can get confusing during holidays, when all generations are in the same room and his children see Joes being treated like a child by his parents.
The Trinity works the same way. Some people interact with God like he is a father. They tend to be more connected to the Old Testament; Creationists. Other Christians see God as the son called Jesus. They relate in terms of an empathy for a child, who suffers but is nevertheless very positive and a source of love. Others worship in terms of the spirit, which is a creative animation of their soul; revivalists. All are parts of the whole and together unite the family of man. During the holidays, like Christmas, they all overlap and interchange; unity.