The first step to picking a main is to not let random people on the internet who know nothing about your skills, preferences, and playstyle do it for you.
My advice is to try out as many characters as you can and pick the top 5 or so you're interested in. It seems you've already done this. Play only them for a while, and I mean like a week or a month. Perhaps only play one for a whole week, then switch. The idea is to get your proficiency with the character past the "honeymoon" stage, so to speak, to get an idea of what you're going to still enjoy a long time down the road. Slowly shrink the list to 3 at most, but optimally you'd have one or two characters that you have a pretty complete and deep knowledge of, as well as enjoy playing. Basically, do what you enjoy, and what you think you'll still be enjoying later.
Alternatively, if you don't intend to be a competitive player, just play as many characters as you want, it doesn't really matter in that case.