They're not, the interactions with the memory model are different, as are the guarantees.

CPS shouldn't be able to deadlock for example?

CPS can trivially deadlock for all meaningful definitions of deadlock.

Would you consider this a mutex?

   async_mutex mux;

   co_await mux.lock();
   /* critical section */
   co_await mux.unlock();
   

   {
      std::lock_guard _{mux};
      /* critical section */
   }

Would you consider boost synchronized a mutex?

Don't confuse the semantics with the implementation details (yes async/await leaks implementation details).