Buckdown, I'm far less knowledgable about pistols (and guns in general) than many around here. But I've learned from experience during the last 20 or so years that there are several overriding factors in picking a pistol.
First -- for me -- is your hand size, and how well the pistol fits. Large hands, large pistol. Small hands, smaller pistol. This was my first lesson. It took me three pistols to 'get it', but I think I've found the right one now.
Second, how well you shoot it. Small angle differences in design and size of grips can make a substantial difference.
Third, how well you deal with recoil, which to some extent depends on your size, and your hand size, but also on how you've been taught to grip the gun. I'm still learning on this one, but for me, 9mm is enough. I've no interest in .40 or .45; not as easily controllable. I like that second shot coming fast.
For me, a smaller guy with smaller hands, I've landed on a Ruger SR9c. Love it.
Get some advice here, but more importantly, after that, go handle some, select a short list and -- hopefully -- try before you buy at a range. Not always easy or possible, but best. I did with the Ruger, and don't regret it.
Good luck.