See if your BGA is a machine with optical alignment function?This kind of machine is too expensive for novices, and the optical alignment function is generally not used.
The key is your understanding of the environmental temperature control and machine performance, as well as the curve setting.
For example, different chips, PCB thickness, manufacturing process curves are different, and the seasons, summer and winter are also different. It takes a long time to test to fully understand your machine.
The picture below is my machine