They are different “branches” or “specialties” of the same discipline. As an analogy, think of a Project Manager like a GP (General Practitioner or Doctor), so a generalist in the field of medicine. Then you have specialists such as for example a dermatologist or a cardiologist. A dermatologist would be like your IT Project Manager and your Technical Project Manager, they are two different specialties, but they are still Project Managers. Kind of like both the dermatologist and cardiologist are also doctors.

A “Technical Project Manager” is a Project Manager specialized in anything technical which could be for example Electrical or IT. IT stands for Information Technology or simply technology, which again is just one of the many fields in which a Project Manager can specialize. But to your point, there is a ton of confusion around this because people sometimes use “Technical Project Manager” and “IT Project Manager” interchangeably as if they were the same thing, which they are not. An IT Project Manager could be considered a Technical Project Manager, but so could be an Electrical Project Manager. Hope this helps and clarifies. Cheers!