Scholars freely admit that the Trinity is never presented as a complete doctrine in the New Testament, but rather is built from scattered Bible verses.
In the NT there is no explicit statement of the doctrine….
Evangelical Dictionary of Theology (p. 1112)
…it is not a Biblical doctrine in the sense that any formulation of it can be found in the Bible….
New Bible Dictionary (p.1221)
The New Testament does not present a systematic presentation of the Trinity. The scattered segments from various writers that appear throughout the New Testament reflect a seemingly accepted understanding that exists without a full-length discussion.
Holman Bible Dictionary (p.1372)
Theologians admit the New Testament does not define the Trinity. Furthermore, there is no clear teaching that salvation depends on the belief in the Trinity.