Is this a good layout for BQ40Z60-based battery management unit?
These are mainly layout nits, nothing glaring. Note that the images are pretty hard to read.


It would be better to arrange the traces that connect to SGND to arrive at the pad in a star topology rather than the ones that share the via at the intersection of UI1_16 and R12_1.


There are also some areas where you could use continuous copper pours to save etchant - just cover them with solder mask where they don't need to be exposed:


The three large PGND pads on the right side of the top layer could be joined with a pour by moving the ADAPTER_ON trace to run up the middle between 1 PH and PGND. Then move the three vias in the empty space in the middle to make more room.
Similarly you could have large SGND and PGND pours in the bottom left.


Finally, what about the mechanicals? It's a complete rectangle board with no cutouts, keepouts, or bosses and some components fairly near the edge. Must be nice. How is it going to be supported?