https://dynasty-scans.com/forum/topics/12835-1-x-discussion?page=125#forum_post_615744
I'm right there with you for this manga, but there's even more going on under the surface. Aside from the obvious that you listed, there's a great many more subtle factors that can and, in real life, almost always do make incestuous (let alone cross-generational incestuous) relationships toxic. The linked post is a detailed breakdown of how the scenario of this particular manga is curated to deftly avoid almost every such pitfall. It's fascinating, really, and I think gives a glimpse into just how much thought and effort Taiyaki puts into this particular series.
literally i was grossed out at first but now i understand the situation as long as it isnt pedophilia the r or abuse or forcing incest is fine