Since "The Trinity" is not a Biblical teaching there is no Biblical requirement to support it; all that is necessary Biblically is to believe that there is a Heavenly Father; a Son and a Holy Spirit. Even when the Council of Nicea in 325 A.D. by vote decided upon the Doctrine of The Trinity there was not complete agreement. In fact, there hasn't been since either. Initially, those who refused to believe the new doctrine of The Trinity were persecuted and executed. Thankfully, that no longer happens but the emotional levels of disagreement can often elevate to nearly that outcome.
The 144,000 will know who they are and what they must do. It is not up to them just as it wasn't up to Saul on the road to Damascus.
I have found these explanations to be very helpful: