Is this 0.5mm pitch BGA fanout OK?
As already mentioned by 1N4007 the pads look rather small, verify the recommendations of the manufacturer, and if not specified, use IPC rules.
Can you give details on the spacing and track width as well, the tracks look rather skinny as well.

Check the layout recommendations for the ground on pin D1. The track seems to be quite long, and might affect the performance of the MIPI lines.

Apart from the details mentioned above, the fanout is reasonable, and you seem to have followed good layout practices.