Nothing in a quest is final. Whether you built it by hand or the AI generated it, every part of it can be reopened and changed — and the same screen is where a standard quest becomes a game mode.
Open a quest you own and you can change its title and description, redraw or extend its route, and open any individual checkpoint to swap its interaction or media. An AI-generated quest behaves exactly like one you drew yourself; generation is a starting point, not a locked result.
The usual pattern is to generate a rough quest, walk it once, then come back here and fix the two or three checkpoints that did not work on the ground.
From the same edit screen, a standard quest can be converted into Flag Raiders or Killer on the Road. The route and checkpoints you already made stay; the mode adds teams, roles and win conditions on top of them.
Each mode has its own walkthrough, so this is only the door. Convert, then read the section for the mode you chose.