I guess the reason the 30-episode-flashback in The Untamed didn't phase me is that I'm Filipino and had to read Florante at Laura in school. I've seen that narrative structure before.
(This is not a recommendation for FaL though. It is bad and is only considered "classic" because it was written in the 1800's. It's basically a self-insert fanfic of Crusades fiction. That's the Crusades at least two cultures removed. Terribad. Maybe only worth reading just to see how that looks like.)
The poem starts with Florante tied naked and bloody to a tree. He's about to be eaten by lions, and is saved by a "Persian prince" and nursed back to health. Florante is the kind of guy to answer the question "so how did you end up in that shitty situation?" with "so it all started when I was in school..." and that's what kicks off the long flashback.
(No, Florante does not get with the prince. Though please point me to the m/m-w/w solidarity fanfic. The guys and gals have more chemistry and interaction with each other respectively than with their het love interests. Let Florante get his hot Muslim prince and Laura get her badass warrior woman. It's only right for Crusades fanfiction.)