i find this lens isnt sufficient enough, lack of sharpness around the edges.
I wonder has anyone ever complained to you about this ? I ask because many people seem obsessed with sharpness and edges which, to the viewer, are utterly unimportant.
I think the problem is not the lens, but your mindset.
I still wonder to this very day what is the ideal gear to shoot such pictures (outdoor & in a studio) and why so?
There is no such thing as "ideal gear".
There's an old saying : *What's the best lens for shot ? The lens you have on your camera it's happening.".
It's what works for you and the subject and the viewer. Not what's ideal in some abstract sense.
Again, if no one has complained about your photos, you probably have as close to ideal as you need.