If there are thousands of three's there are hundreds of thousands of two's and these are ones that are fundamentally and easily understood by anyone with no scientific background or knowledge.
The earth and the moon.
Day and night.
Man and woman.
Black and White.
Hot and cold.
Good and evil.
Mother and father.
North and south.
East and west.
Positive and negative.
And consider that two is the only even number that is prime. And again that's not to mention the duality built into all animals and humans.....two hands, two arms, two lungs...etc. etc.
Combined with the overwhelming scriptural descriptions of the Godhead as seen in heaven (FATHER AND SON) the evidence is overwhelming that the Godhead is two, not three.
You said thousands of proofs of duality as the basic nature, you listed some examples, like
Positive and Negative. Every heard of Ground? Without it there could be no potential (positive and negative)
Mother and Father. If no children (offspring), no life would exist
Man and Woman (I assume you mean male and female as in life)
Plenty of non-sexual life exists — M,F, and Asexual.
North/South/East/West are concepts describing flat progress on a curved surface (the earth) that exists in 3 dimensional space. In other words for YOU to go straight north on earth, requires movement in 3 dimensions simultaneously.
Black and White. Does the universe really exist, in any way/shape/form as only black / white. Can you point to an object in the universe emitting or reflecting 100% black or white? No, you can’t. These are concepts we can only approximate.
Good and Evil? Some actions are neither. They are devoid of morality. Is a planet good or evil? A person’s actions may be good/evil or neither.
Yes, there is BI-lateral symmetry in humans/animals but all exist as three. You would not be alive to move your hands without a soul and spirit.
What of Matthew 28:19 - go and make disciples of all men, baptizing them in the NAME of the Father, the Son, and the Holy Spirit. In the greek, it uses the singular NAME, and the definitive for each of the Father, Son, and Holy Spirit.
Clearly in this verse we are taught three in one. There are many other proof texts that draw distinctions between God the Father, God the Son, and God the Holy Spirit. If you don’t think the Holy Spirit is a full person in the Godhead, please review Acts 5:3-4, where the Holy Spirit is lied to.
Also, the Holy Spirit can be grieved. Eph 4:30
When writing about the Holy Spirit (our helper), in the greek, the masculine form is used, rather then the neuter, which would have been correct had the writer intended to imply the Spirit were a impersonal force, rather than a person in the Trinity.
I studied the Trinity for years, because I have family members who belong to a small sect that reject the definition of the Trinity. So I spent a long time looking at the situation from both sides, and have arrived at what we call the classical definition of the Trinity. One God, somehow existing as three individual “persons’. I put quotes around persons because God is not a person as in you and I are. This is one reason for the confusion.