There are a lot of different things it can improve the timing. You just have to try them and see.
The first thing is to make sure that the mesh is strong so the signal can get relayed as quickly as possible.
When you paired your devices, both the bulbs and the motion sensor, were they sitting physically in the same places where they are now? Or did you pair them close to the hub and then move them?
It may be that they don’t know who the real neighbors are, in which case you need to “heal” the network and that can clear up a lot of latency. But you may not see the results of the improvement for several hours.