I remembered some BGA tool thingie from a recent post.
A simple search & re-found it in:
https://forum.kicad.info/t/bga-vias-as-part-of-footprint/10083
Have you looked at some other BGA related threads on this forum?
https://forum.kicad.info/search?q=bga
Your footprint looks weird, but I am unfamiliar with your color scheme.
Yellow is the copper I presume, and purple the solder mask ?
The pads look much too small and exposed copper on the traces seems … unacceptable.
I’m not very familiar with BGA’s, but I think it is common to use 6 or more layer pcb’s and (micro / buried) via’s to fan out the pins, just as in other posts here. That seems to be the only way, you are never going to get more than 2 rows of the BGA fanned out per layer.
You also may want to have a look at the Olimex Olinuxino A64 design on Github.
It is a fairly dense PCB with several BGA’s done with only 6 copper layers in KiCad.