I personally recommend the Taurus PT-709 Slim. 6+1 rounds of 9mm, and it has worked flawlessly, for me. It is 1” thick,and with the proper ky-dex holster is almost invisible. When I bought it, I put over 500 rounds through it, with no FTF’s, ever. I didn’t even clean it after the first month to test it’s reliability. I’ve had it for over 5 years, and I would stake my life on it. Also, it was my preferred carry piece when I traveled to Detroit.
One other nice feature of the Taurus PT 709 Slim is it’s unique single- action/double-action trigger. If it fails to fire when needed, you can pull the trigger again for a double-strike capability. And, it works as advertised, I’ve tried it.
I have the PT-740, which is the .40 S&W version of that. It’s very concealable. Muzzle flip is a but much, but I’ve got meaty paws so I can handle it. Biggest problem has been finding extra mags.
CC