Immature position. Yes you can build your own, because you want it to use your private data for learning. That is a real thing. Create your own personal assistant with access to your private data ensuring no one else can get to it. But, that $85k of hardware is very limited and will need management and upgrading to grow. That is where the cloud service is way better. Plus, if it is important enough to build your own you also need to secure it. Good luck there.