Revelation is progressive. Every aspect of Jesus himself is not recorded in the OT.
There may be hints of the Trinity in the OT.
https://www.christian-faith.com/the-trinity-a-bible-study-outline/
A cursory list follows:
The word Elohim is used thousands of times for “God”; Adonai is used hundreds of times for “Lord”; both of these words are plural nouns in Hebrew.
A number of passages speak of the “faces” or “presences” or “persons” of God (Exodus 33:14; Deuteronomy 4:37; and Job 13:8).
God refers to Himself as “Us,” “Our,” and “We” (Genesis 1:26, 2:18 (LXX), 3:22, 11:7; Isaiah 6:8, and 41:21-24),2 a phenomenon that is reflected in virtually every English translation.
The OT says of God, “they caused me to wander” (Genesis 20:13), “they appeared” (Genesis 35:7), “they drew nigh” (Deuteronomy 4:7), “they went” (2 Samuel 7:23), and “they judge” (Psalm 58:11).
The OT calls God our “Creators” (Ecclesiastes 12:1), “Makers” and “Husbands” (Job 35:10; Psalm 149:2; Isaiah 54:5).
The OT says that God is “holy” (Joshua 24:19; Proverbs 9:10, 30:33), another plural.
https://www.answering-islam.org/authors/rogers/ot_trinity.html
D. References to the diversity of God
1. Old Testament
Gen. 1:1 - "In the beginning God (Elohim - plural) created..."
Gen. 1:26 - "Let Us (plural) make man in Our (plural) image"
Isa. 6:8 - "Who will go for Us (plural)?"
Isa. 9:6 - (Messianic) "Mighty God, Eternal Father, Prince of Peace"
2. New Testament
Matt. 3:16,17 - "being baptized, Jesus...saw the Spirit of God descending...and a voice,
saying, 'This is My beloved Son...'"
Matt. 28:19 - "baptizing them in the name of the Father and the Son and the Holy Spirit"
II Cor. 13:14 - "the grace of the Lord Jesus Christ, and the love of God, and the fellowship
of the Holy Spirit, be with you all"
Gal. 4:6 - "God sent forth the Spirit of His Son into our hearts..."
Eph. 4:4-6 - "one Spirit...one Lord...one God and Father of all..."
I Pet. 1:2 - "foreknowledge of God the Father, by the sanctifying work of the Spirit, that
you may obey Jesus Christ..."
I Jn. 5:7 (KJV) - (without adequate MSS evidence; interpolation)
a. Father as God
Jn. 6:27 - "the Father, God, has set His seal"
Eph. 4:6 - "one God and Father"
I Pet. 1:2 - "God the Father..."
b. Son as God - (cf. I Jn. 5:20; Phil. 2:6
Jn. 1:1 - "the Word was God"
Jn. 20:28 - "My Lord and my God"
Titus 2:13 - "our great God and Savior, Christ Jesus"
Heb. 1:8 - "of the Son, 'Thy throne, O God, is forever..."
II Pet. 1:1 - "God and Savior, Jesus Christ"
c. Holy Spirit as God
Acts 5:3,4 - "lie to Holy Spirit...you have lied to God"
Rom. 8:9 - "the Spirit...Spirit of God...Spirit of Christ
I Cor. 6:11 - "the Spirit of our God"
II Cor. 3:17,18 - "the Lord is the Spirit"
http://www.christinyou.net/pages/trinity.html