You're asking what is best, and Conan has the answer:
Other than that, there is NO answer, as it's a personal opinion/choice.
If you're new, take your time. The concept of "stopping power" is a fuzzy one. The concept of kinetic energy is easily defined. The interplay between stopping power and kinetic energy is extremely complex, because you have to factor in stuff like, bullet design (jacketed? Hollow point? Something else?) and shot placement.
I once read that may small holes are more effective than large misses.
If you're starting out, and belong to a Club, let it be known that you'd like to try stuff; most likely that you'll be offered a crapton of opportunities.
Some people like Glocks; I don't (wrong "feel" for me). My kid won't carry my carry piece, as he's "Not familiar enough with the platform" to be comfortable.
Find something that "fits" you and get decent with that. After a bit, you'll be able to make a (more) informed decision, based on your own wants, needs, skills, and "intuition," for lack of a better term.