Galvatron is a character that appeared in the Transformers: The Movie (1986), which is also part of the G1 continuity.
Unicron is the main antagonist in Transformers: The Movie (1986).
So, while Galvatron and the Dinobots are both part of the G1 Transformers lore, Unicron is the primary antagonist in the movie, not Galvatron or the Dinobots.
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