I'm not sure I understand your question.
Jesus does not agree that there is no Trinity (see Matthew 28:19).
What of Peter, whom Jesus had instructed in The Way, and as such did baptize in the name of just the father in Acts 2:38?
And Peter said to them, "Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit.
Matthew 28 isn't telling teaching the Trinity. The Trinity doctrine entered scripture some 400 years after Christ. It has a historic presence in the canon.
Whereas Jesus (the) Christ was God incarnate, in the flesh. And as was witnessed by those attending including John the Baptist, when Jesus was Baptized by him, Holy Spirit God descended upon Jesus in the form of a dove. To give a visual presence to the teaching of Jesus as pertains to be Baptized and receive the gift of the Holy Spirit. And there it was. Jesus, the Messiah/teacher, baptized and receiving the Holy Spirit. Coupled with the voice from Heaven affirming the same. This is my son in whom I am well pleased.
It was all what we're told in the OT. One God. Not three separate and distinct persons, ever.
Matthew 28 isn't teaching to baptize in the name of three separate and distinct persons. It is teaching Baptism occurs in the name of I Am, the One! That is Holy Spirit God, who on earth was the son of God, the son of man, Jesus.
If it was intended to communicate separate and distinct persons in Matthew 28 the instruction would have also included, son of man. In order to define, differentiate, the image and likeness of Christ appearance on earth.
God is Holy Spirit.
Ezekiel 36:26-27
And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.
In Matthew 6 Jesus taught his Disciples and others how to pray beginning with,
our Father who art in Heaven....
Not, our Father, our Holy Spirit, and his son who art in Heaven....John 1 in the first five verses quashes the later interpolation that is the Trinity Doctrine.
Yes, the Trinity declares not that the Father Son and Holy Ghost are separate but that they are distinct from one another.
And that is not at all true. The Trinity declares they are three separate and distinct persons.
Which is also untrue. John 1 assures that is a fact.