The doctrine of the trinity doesn’t actually stunt the growth of Christ because nothing and no one can stunt the growth of God. However, the trinity doctrine does stunt the growth of our understanding of Christ. That is, the growth of Christ in our minds is hindered and cut short by the trinity doctrine. This is just the sort of stunting that the writer to the Hebrews was warning against (Hebrews 6:1), even though the trinity was a doctrine which had not yet taken shape in biblical times.
The idea of the trinity keeps Jesus as a Son and won’t let Him be a Father. God’s plan for Messiah – which is to say His plan for Himself – was to grow from the smallest seed to the largest plant (Mark 4:30-32). God would live as a man, be killed, and then raised from the dead to ever-increasing glory as He took the throne of a new universe (Ephesians 1:10; Revelation 21:1) just as He had held it in the old universe.
Let us cast aside the trinity as a vain idol of religiosity, and press on to know the Lord (Hosea 6:3).
For more on this subject, see: