This does not compute very well.
When you get files from customers, you pretty much have to deal with whatever you get. One possibility is to only accept Gerber X2 files from customers, but you risk loosing customers that way. And as retiredfeline already mentioned. There is not much KiCad can do with existing gerbers. Usually it is the endpoint of KiCad.
KiCad does have:
But the process is far from automated, due to a lot of missing info in Gerber files. That method is nice to “rescue” a project, or a last resort to revive some project, but for daily work it is far to time consuming.
So, what is the business you are in? What are you doing with those files?