If you believe that you really must be unfamiliar with the New Testament.
(John 14:9 NIV) Jesus answered: "Don't you know me, Philip, even after I have been among you such a long time? Anyone who has seen me has seen the Father. How can you say, 'Show us the Father'?
(John 10:30 NIV) I and the Father are one."
(Matthew 28:19 NIV) Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit,
(Acts 15:28-29 NIV) It seemed good to the Holy Spirit and to us not to burden you with anything beyond the following requirements: {29} You are to abstain from food sacrificed to idols, from blood, from the meat of strangled animals and from sexual immorality. You will do well to avoid these things. Farewell.
(Acts 5:3 NIV) Then Peter said, "Ananias, how is it that Satan has so filled your heart that you have lied to the Holy Spirit and have kept for yourself some of the money you received for the land?
(Acts 5:32 NIV) We are witnesses of these things, and so is the Holy Spirit, whom God has given to those who obey him."
(Acts 13:2 NIV) While they were worshiping the Lord and fasting, the Holy Spirit said, "Set apart for me Barnabas and Saul for the work to which I have called them."
I'm not unfamiliar, I just have seen it in a different light. I'll try to touch each of the verses, only quickly though. To believe in a Triune God, I would counter by saying that you must be unfamiliar with the beliefs of Judaism. Seriously though, the Bible doesn't teach a trinity and that's why it's called a mystery. I don't subscribe to mystery religions. Give me a chance and you will see that what I say is truly biblical.
Side note: I'm really not a fan of the NIV, I think it's terrible, so I will only use the KJV for my responses. No offense to you, but it's just the Bible that I primarily use.
Being one doesn't mean one God or one being . The text doesn't say or imply this. In fact Jesus prayed to God that we would be one with them as they are one. Surely we aren't to become God. One in mind and spirit.
Again, there is no text here saying that these three are God, only to baptize in the name of the three. I want to point out that this verse is also considered a textural corruption. There are no recorded baptisms in the Bible that use this baptismal formula. All baptisms after Jesus' resurrection were done in the name of Jesus only as recorded throughout the book of Acts. Greek historian Eusebius quoted Matthew 28:19 many times in his works and always quoted it as only saying "in my name" which aligns with the rest of Scripture.
Your remaining Scriptures hint at the Holy Spirit being a person, yes? God breathes out His Spirit, sheds forth His Spirit, pours out His Spirit, and dwells in us through His Spirit. This Spirit is not a separate person or being, but is God’s own power and presence. Our bodies are called temples of God because God dwells within us through His Holy Spirit (Psalm 51:10-12). It was by the power of God’s Holy Spirit that Jesus was conceived in Mary and he was anointed by this same Spirit at his baptism. The Holy Spirit is never named, never greeted, and never worshiped and doesn't have a separate throne in heaven. It is an extension of God himself.
I say all of this not to win a debate but to show you that I speak with love of truth and wish only to share what I have learned with others who may be seeking. I don't speak emptily or blindly. You may not agree with me but please at least see where I am coming from and know that I only seek to glorify God and His Son in all that I do. It makes sense.