I would visit a range that has a variety of handguns to rent and kind of get a feeling of each of them and see how they feel to shoot.
Holsters are another story. Many, many choices. Everyone has their go too company.
Hopefully you have friends that shoot, and you can try out some pistols. You have to find what you love, or can at least be happy with. There is no standard answer to the question you ask. We pick wives, girlfriends, trucks , and yes even guns, and calibers, from what makes us happy. The journey is yours to enjoy.
The answer is a 1911. What was the question again?
Also, welcome to INGO!