Desktop application with python script integration and multithreading

Hello, we want to build a brand new application. The application has to run on Windows, Mac, and Linux. We need an installation system, with a key-user system. Other than that, we want to publish updates directly from our server. The main and most important thing is that this application has to contain and launch several Python scripts simultaneously, using the whole power and as many resources as possible on the machine (multithreading). So we have to include those Python scripts safely so that they are not readable and extractable from our application. The application needs to be really basic, we need it as light and simple as possible, focussing on power and optimization. Last but not least, the application has to make some calls to a database, obviously because of the key-based system but also for other data. Thanks