It depends on the layout of the phone though. Size of camera module, placement of fingerprint sensors, other sensors/modules, heat sinks. You name it, really.

As such the batteries tend to be oddly shaped, and even spread out in different places to get as much battery in as possible.

The “best one” differs from phone to phone.

There isn’t one “best one”. Always depends on requirements, which vary by device, underlying technology and use case.