Crawling out of the deepest, darkest depths of writer's block

Hellooo! Uh, so idk why I'm writing this, but I really need y'alls opinions. I have been trying to write a book since I was like 15. Every time I get back to writing, I end up changing things and re-writing the plot over and over again. Now I don't even know how the story is supposed to go! I have all these characters that are all well developed, but I don't know how to write their story. All I know is that I don't want to change the theme or the main concept/idea of the book. How could I get out of this writer's block?

For a bit of context on the story, I mainly had an idea of this circus/band that travel through the multiverse, performing in different worlds. What I'm really stuck with is the conflict. Because I really want there to be this plot twist that you wouldn't see coming. I want for the most loved character that everyone trusts to have these dark secrets from their past. It's very hard for me to write their idea down because I find it easier to visualize it. To see and hear it. So like in my head, I've got this wild ah musical and I just wish I could just transfer it all from my brain into a well written novel with like 60,000 words. But I can't because yeah. So if you have experience in writing or not at all but still have some advice, I'd really appreciate anything you can give bro.

Alright I'ma go sleepies now because it's 1am over here 💤

God bless y'all :]