Latimer

I have a security issue. As a result I need to remove or disable the Onstar and GPS systems. I contacted a custom shop that said that they have not been able to successfully disable these systems since around 2014 or so, he said that since that time, GM has integrated many critical features with these modules, making it very difficult to do without loosing critical systems. He mentioned that there may be software solutions. I need to figure this out, any thoughts, or out of the box thinking would be appreciated.