It's admirable to pursue this goal, but achieving it objectively will be very difficult. I recommend starting with a university program (with serious dedication).
If I were to go back to my summer vacation after high school, I would definitely find a lab doing RF work and get some experience while also using their equipment for free.
It's incredible that someone can manually assemble and operate a USRP/Pluto system for transmitting and receiving signals. Building a complete communication setup from scratch is truly remarkable. I don't think I could do it.
Let's not even talk about the technical difficulty first. How do we acquire the measurement equipment? There aren't many affordable RF instruments available.