Who is the liar but he who denies that Jesus is the Christ? This is the antichrist, he who denies the Father and the Son. Whoever denies the Son, the same doesn't have the Father. He who confesses the Son has the Father also. — 1 John 2:22,23.
Obviously, there is nothing in what John wrote that says that a person is antichrist who does not believe that Jesus is the God of Abraham, Isaac and Jacob. "The Christ" signifies "The Anointed", that is, the Anointed of the Lord Jehovah. (Psalm 2:2; 45:7; Isaiah 61:1; Acts 2:36; 10:38; Hebrews 1:9) John did not write about denying any doctrine of men that has to be imagined, assumed, added to, and read into the scriptures, such as the triune God dogma, or the oneness dogma. He was talking about denying the Son, which, in effect, also denies the Father, since it was the only true God who sent the Son (John 17:1,3), and the only true God performs His works through His Son. — 1 Corinthians 8:6.
To deny that Jesus is the Christ, Jehovah’s Anointed One is what John was writing about; he said nothing about denying an alleged triune God. Indeed, if one accept Jesus as the Messiah, the default reasoning should be that Jesus is not Jehovah who anointed and sent Jesus.
Rather than identifying Jesus as being Jehovah God, we find that the scriptures show that Jesus was sent by Jehovah, that Jesus speaks for Jehovah as one person, his God and Father, and that Jesus therefore represents Jehovah, acting for and speaking on behalf of Jehovah his God. It was the God of Abraham, Isaac and Jacob who raised and glorified His Son, and thus the God of Israel is identified as being only one person, distinct from the Messiah whom God anointed and sent. Although many like to read the thought that Jesus is Jehovah into many scriptures, actually Jesus never claimed to be, nor do the scriptures present Jesus as, the God of Abraham, Isaac and Jacob, whom Jesus represents and speaks for. — Deuteronomy 18:15-22; Matthew 22:32; 23:39; Mark 11:9,10; 12:26; Luke 13:35; 20:37; John 3:2,17,32-35; 4:34; 5:19,30,36,43; 6:57; 7:16,28; 8:26,28,38; 10:25; 12:49,50; 14:10; 15:15; 17:8,26; 20:17; Acts 2:22,34-36; 3:13-26; 5:30; Romans 15:6; 2 Corinthians 1:3; 8:6; 11:31; Colossians 1:3,15; 2:9-12; Hebrews 1:1-3; Revelation 1:1.
Of course, since the only way to the God and Father of Jesus (Micah 5:4; ! Peter 1:3) is by means of Jesus whom the only true God sent (Isaiah 61:1,2; Luke 10:16; John 3:17; 5:23; 14:16; 15:23-24; 17:1,3; 1 John 4:10), then to reject Jesus is the same as rejecting the Almighty Jehovah who sent Jesus. Nothing in any of this, however, means that we need to imagine and assume that Jehovah, the God of Abraham, Isaac and Jacob is three persons, and that one of the persons of Jehovah is Jesus.
One trinitarian states concerning 1 John 2:22,23: “That is to say, he that denies Jesus to be the Son of God, which means equal with God (John 5:18, John 10:30 & 33), is antichrist!” The Jews made the false assertion that Jesus claiming to equal with God; Jesus himself denied that assertion by saying that he was the Son of God and it was God who had sanctified Jesus and who had sent Jesus. The reality is that if Jesus had been claiming to be equal to his God, that would make two Gods (two Supreme Beings). One would have to keep adding more to what the scriptures say to make it appear that it would mean that Jesus and His God are the same “one God” from whom are the all.
See also my study:
1 John 2:22-24 – Denial that Jesus is the Christ
We also have a resource page that provides links to studies related to the assertion that Jesus is equal with his God: Equality to God (Equality with God).