As a lefty I find it easier to purchase pistols over rifles,
A G43 fits your description perfectly at 600ish, single stack 9, proven track record for CCW.
Not a true lefty only if you wish to release the mag with the left thumb, use your left index finger and things are golden. I've been told G43 safety's can be flipped, If I'm wrong someone correct me please.
A true lefty could be an 1911 style with ambi safety, and I love my 1911 style pistols, you will likely still have to use the left index finger for the mag release.
Since most guns will have mag release on the left side, I prefer to have all my pistols that way, Kiss theory.
There are all true lefty pistols available, but as time goes on, if you don't remain 100% loyal to those ergos and standards, you'll find yourself with a blend of pistols and functions.
Likely not the best scenario with handguns.
Get yourself to a quality gunstore and start looking.
I'll let others explain the striker fired mechanics.
