Home, a bit sick:
After a random idea at 5am I'm now back on a Egyptian decans project I half abandoned years ago, and now it's finally giving answers. I vibe coded a more rigorous version of a tedious manual approach: fully computed skies for Thebes, Abydos and Memphis, 518 stars, the decan list fitted as one sequence. It low key checks out.
Three decans now stand firm: Sothis is still Sirius, "the red one" is ε Scorpii, and tpy-ꜥ ꜣḫwy is Fomalhaut. Between them runs a road of stars through Hydra, Centaurus and Scorpius to Sagittarius.