Using educated guesses, it seems clear to me that Simmons never wanted to be with the team ever again, but was persuaded/arm twisted to report so they could claim they did their part and force the 76ers to act. When that failed and Simmons was compelled to go to practice and face the music, Simmons made it miserable for everyone so the 76ers would have to remove him and he could roll out this mental health angle to stay in compliance, but not have to do anything else.
Simmons & his agents are banking that Morey and the 76ers will cave before they do: If the 76ers struggle, internal and external pressure will build on Morey to remove the distraction and/or improve the team, especially as the trade deadline comes closer. Even if the 76ers win without Simmons, the pressure will mount to go all in this season and get whatever value they can for Simmons.
Both sides appear resigned to the inevitability of playing out this well trodden string of moves and countermoves until reality sets in. It is like a badly played chess game headed to a draw.