Yo twin, I actually figured ts out, so basically I was confused at first but if we take away the omegaverse element of the sidestory, it represents their life actually canon to what happened originally in the main story. The sidestory, not canon to the events showcases their life in the continuation of the canon main story after the end. So its upto interpretation but yeah! What I mean is this is what happened in the omegaverse au. They had a miscarriage and the baby was lost, of course after the canon main story events. Now in the end, the author wrote that this is canon if we take away the fact that Je Oh was pregnant. This means that after moving to Hong Kong, Both of them felt loneliness and couldn't have a baby because the og au is not ABO au, which was represented by the miscarriage in the omegaverse au. They couldn't adopt or have a baby and same goes for ABO au. Though the baby in the end is probably the baby of the woman who was the villain in jail.

How is canon and not canon at the same time I'm genuinely asking for help