Glocks are great for lefties. Exteded OEM slide release makes it perfect.
The only wish I have now is for a lighter MAG spring or a bigger button that doesn't stick out as far as the current aftermarket ones do.
The only 911 style I've shot and bought that is as good for left handed is the Tarus PT945. Its ambi saftey and decocker, the mag button is in a good spot and decent pressure. The slide release has an extended teeder todder design I can pull the front down on trigger finger to force the release to catch open for inspection.
Glock is better though all in all and I prefer the 40 cal anyhow.
If everything is going right, you must be doing something wrong.