Your question is a rather tall order for a short pithy FR reply. Get a rig, play around, get back to us in a year or so. You won’t be getting your news via Olivia MFSK or jt65a anytime soon.
Ditto to what SpaceBar said. Jump in and get wet, getting your first license, Technician, isn’t hard at all and you could get the second level, General, in the same test session with a little study. Then, you’re all set to experience the full breadth of the frequency spectrum and the various technologies that appear to interest you. Be aware that most of them have a steep learning curve and can have a steep acquisition cost curve, too. Used equipment can reduce that some but wanting to be on the leading edge usually means $$$$.