this isn’t a rumor. The author herself clarified this on her Twitter. Here’s what she said:

''Since many of you seem to be looking forward to it, I’ll say this in advance: Path of Flowers in the White Night is not an mpreg story. However, it does serve as the starting point for the creation of that fig fruit. That part takes place much later, after Shurakawa Tei’s death, and follows the story of future generations.

The setting does not become an Omegaverse until after a new world has been established. The story is divided into three parts: the current timeline → the event that leads to the world’s destruction → the beginning of a new world. Each part has its own distinct setting and storyline.

This is still in the planning stage, but I’m also preparing to serialize the second part, which will cover the cause of the world’s destruction.''
 

so in conclusion From what I understand, the story is structured in three parts:
1/ The first part focuses on Shuraka and Tei
2/ The Destruction (a possible future story)
3/ The Omegaverse (Seth & Theo)

  You’re welcome, I really appreciate that 😄 honestly I feel like a most of people aren’t reading the story very carefully. They just jump to conclusions too quickly without really trying to understand what’s going on.

Both characters clearly have trauma and they’ve suffered a lot when they were younger and tso their actions aren’t that simple. And one important point is that a lot of people miss the fact that they both have family issues too, especially with their parents, which affects how they act and see things.

That’s what makes the story deeper. And since it’s still the beginning, it’s normal there are misunderstandings and miscommunication between them.

Plus, the author already said it’s going to be a long story, so I think people just need to be more patient, read carefully, and not judge everything so quickly.