There is no GSX500 in North America. I’m pretty certain there isn’t one anywhere actually.
GS500E/F is a sporty standard. It is intended as an everyday commuter / sporty ride / low budget touring bike / beginners bike. Take your pick of duty, it does them all reasonably well. E and F designate generation I believe. ShannonG or Ben could probably tell you more.
GSX-650F is the Katana/Bandit replacement. It is an everyday sport bike or budget sport tourer depending on your want. In either case it is not really intended for beginners.
GSX-600R -750R and -1000R are supersports intended for experienced riders. They are aimed at track day riders and people who want serious performance at the cost of practicality. The R suffix in this case means “Race”
All are great fun and reliable bikes. Of all of them, the GS500 will have the lowest insurance, best gas mileage, and be the most forgiving.
“The two seconds between ‘Oh S**!’ and the crash isn’t a lot of practice time.”