Question Does these SFX really made up from author or they have a meaning ? どばーでばばーん/doba + baban

I don't understand what does this character implied/ talking about here in this story. Hope some native or experts >N1 in Japanese could explain. Thank you so much !!!

A girl is retelling about her memory in the past with her step-little sister. When they're still little girls, they climbed together on top of a mausoleum, in order to view the parade of a king around the countries he conquered, to remind the people that he's the new king of the continent + display his power. She saw a convoy of golden horse carriages very impressive, and thought to herself that she want to get a parade like that one day too. (and i only get the part kirakira/きらきら = sparkling horse carriage )

Girl「わたし、むっちゃ巡幸の行列が見たくなって、義妹と一緒に、ばれたらやばいのに霊廟の上に昇ってね」

「そしたら、きらきらでどばーでばばーん、でさぁ……あれ絶対欲しいぃって思っちゃった！」

All those onomatopoeias, including きらきら, mean showy, gorgeous, deluxe or like that there. きらきら expresses the image of the whole parade, I think.

Toritoribe said:

All those onomatopoeias, including きらきら, mean showy, gorgeous, deluxe or like that there. きらきら expresses the image of the whole parade, I think.

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on 2nd thought, i think since the girl talking about a parade for a king around the countries he just conquered , there must be lots of horses and escort soldiers ? Do you think the SFX in the sentence そしたら、きらきらでどばーでばばーん、でさぁ mean something like :
"Then when i got on top of the roof, i saw a parade full of sparkling horse carriages, and awesome marching sounds like thunder ...." (i imagine どばーでばばーん/doba + baban the girl implied about the horse + soldiers steps sounds ?)

Hope you can correct if i was wrong , normally i read manga and i just skip sound effects text - but i really want to understand how a native Japanese understand these SFX

きらきらしたパレード is a common expression. It's used as the same meaning as 華やかなパレード. It's not always needed that there are sparkling things there.
どばー expresses the number of things/people is huge.
ばばーん means "impressive", often when the subject sees it or it appears in front of them. It's not always used for sounds.