Bear in mind that Colt Official Police and S&W Military & Police (Model 10) guns were FBI standard for generations and agents also often bought M-19 and M-66 guns. I think the agent who ended the 1986 Miami shootout killed the perps with a Model 686, even larger.
I don't know your build or your budget. I don't know your mindset, but here you are, asking this question. That says something. Don't let your body language telegraph that you're armed.
I once worked a security job for several weeks where I wasn't supposed to be armed, although I was supposedly protecting a pharmacy that had been held up repeatedly and had bullet holes in the wall over the pharmacy.
I wore a S&W Model 64 with four inch barrel under the short uniform jacket in a Bianchi Shadow holster. It rides high. No one ever suspected that I was armed. I later transitioned to a Model 66 .357 for that holster. (Yes, I changed jobs ASAP.)
Really, I feel pretty comfortable with an appendix carry in an inside the pants holster. You need a sweater or long, opaque shirt to cover it. When you're wearing the gun, stand in front of a long mirror and study how the clothing drapes or rides up. Does the gun "print"? If not, you're good to go.
Remember, the casual public won't study you to see if they think you're armed. A shrewd cop may, so you want to avoid telegraphing the presence of the weapon and be sure to always carry your license, of course.
This does not mean that you can always hide the gun as well as a smaller one, but a medium-framed .357 is the best all-round handgun, I think. If you can later buy a smaller .38 or a .357 Ruger SP-101, do. But don't sell this present gun to do it. Oh: don't load Magnum ammo if you're likely to fire the gun indoors. You probably already know that a .357 is LOUD!
Good luck.