Ask HN: How to get a general tech background?

I have been in the IT industry for years as a non-technical, BA, PM and now manager. While I understand things at a really general level, I still struggle with basic technical knowledge gaps. What would be the best way to approach self-directed learning for overall IT development, from infrastructure/networking through basic programming languages and approaches through web technologies. Just something to have a comprehensive, if not super deep, understanding of the whole picture. Is it better to start from the foundations of infrastructure or move from understanding applications (object-oriented design, java..etc) and then onto how things work together?