If I were in your shoes choosing a firearm for range fun, I would not get a third handgun. For some variety I'd research and buy a rifle.
If you insist on acquiring a handgun, you can't go wrong with a Glock 19.
Just compact enough to concealed carry, but big enough to fill your hands. Uses the most popular self defense handgun cartridge, holds plenty of 'em and is super reliable. I carry one everyday.
I believe 40 S&W is the third most popular self-defense cartridge for civilians and
the most popular for law enforcement. Seems like it's constantly gaining popularity.
I don't have much experience with a huge variety of handguns so I'll stop there. But just buy a G19.
One last piece of advice I'll throw out is it's a terrible time to be a firearms buyer right now. I'd wait at least until the fall to see where prices go. Currently almost everything firearms related is ridiculously overpriced.