It looks like a lot of your switches are of the older non plus type and they're down at 9kbs and at best some are 40k. This is a serious bottleneck. You could throw some repeaters in but they still won't be that good. Ultimately the bottlenecks are causing the delay.
I would use groups to group the lights together with a single activator. That should stop the popcorn effect and the odd one not turning on.
Take a look at this article... Look at the z-wave section. Are you new to home automation or Hubitat or coming from a different platform such as Wink, SmartThings or Vera? This may help!
