Wiring diagram to split one circuit for ceiling lights in multiple rooms?
A star topology is fine, but you don't need to route packets with power. Choose a layout that uses the least amount of cable. There's no reason to do anything else. All the lights may be on the same circuit. The fact your diagram has two nearly parallel lines going to the upper lights tells me this is not the most efficient. You should carry power to the upper right light from the upper left instead of coming from the junction box.

Similarly, if the run from the upper right switch to lower right light is shorter than junction box to light, that would be a better layout. BTW, where's the switch for the left light?

You basically just need to run two conductors everywhere, and in addition a third conductor for when you need to carry power through next to a switch leg. If a light or switch is at the end of a run, you do not need the third conductor.

For example, if you were to run power from the upper right switch to lower right light as suggested, the run from upper right light to upper right switch needs to be 3 conductors to carry power through along with the switch leg. From upper right switch to lower right light is 2 conductor because no switch leg is there, The run from lower right light to lower right switch may also be 2 conductor because the switch is at the end of a run and power is not needed further on.