That song, whose Japanese title is something like "Beautiful Life," has lyrics that seem to reflect on the suffering and hardships of someone who was once called a "ruler" or "powerful person" and has fallen from grace.
Dozle Zabi, who piloted the Big Zam, was still drawn to the "manliness" of the Zeon people and soldiers as a "warrior," so I think he's different from the person depicted in the lyrics...
"With just one word from me, who was once the ruler of the world, I was able to make the sea rise,"
I tried to overlay that song, which begins with lyrics that could be translated as such, with this digital diorama in the original work.

I can hear the beginning of the lyrics to Coldplay's "Viva la Vida." | ふっださん's Gunpla works