I think there are really only 2 things for you, either switch into a job that allows for you to grow from technical mentors or get into open source (or a side

I think there are really only 2 things for you, either switch into a job that allows for you to grow from technical mentors or get into open source (or a side project) that will allow you to develop deep knowledge of a language/framework/architecture. A lot of my technical growth comes from side projects I work on (for myself or open source).