It's a little on Conte for me. He could have diffused things by saying to Oshimen "give me one more year, I'll help you get back to your best and then you can go wherever you want" but instead he's completely alienated him.
For me, no one has come out of this looking good. D Laurentis has had an absolute mare, and Oshimen has, at best, been following terrible advice. All in all, it's a shocking fall from grace for Oshimen, Napoli, and Conte.
I do think Conte is a fundamentally good coach when he isn't falling out with everyone, so I wouldn't be surprised to see Napoli do OK this season, but their financial situation must be absolutely fecked given they were doing incoming deals on the basis that they expected to sell Oshimen, and now not only haven't done so, but have kept his outrageous wages on the books. It could really ruin them for future seasons, so they really have to hope Conte can help them win now.