I think the paper was probably done honestly, but also very poorly. They claimed synthesis of 36 new materials. When reviewed, for 24/36 "the predicted structure has ordered cations but there is no evidence for order, and a known, disordered version of the compound exists". In fact, with other errors, 36/36 claims were doubtful. This reflects badly for authors and worse for peer review process of Nature.
https://x.com/Robert_Palgrave/status/1744383962913394758