The Bible is the court of final arbitration, so if something is true it has to be in agreement with the Bible. Otherwise, it is false. So if Trinitarians want to provide evidence for the Trinity doctrine, their argument should be in agreement with the Bible. Likewise, if we believe the Trinity is false, our belief should be in agreement with the scriptures.
“All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work.” (2 Tim 3:16-17)