I have close to 100 LIFX bulbs installed, and my Candles are actually some of the least problematic ones I have. (Also on firmware 3.7). One possible area to investigate would be the Maximum concurrent connections that your wireless router, or extender can handle, then (depending upon WiFi hardware) checking to see if your bulbs, in this area, along with other WiFi devices in the area are maxing out the number of concurrent connections that your device supports.
I’m using a semi-dense distribution of eero pro units, around my property. I never run into issues with WiFi overload. The only problem I have, is that I have exceeded, by far, the maximum device limit for an Apple HomeKit Hub. This forces me to use other control devices, such as Alexa, which must retrieve all information from the cloud. This results in a very slow and staggered response. Being 1-way communication, any missed signals to one or more bulbs, means that I must repeat my trigger phrase.
I truly wish LIFX would develop some multi-platform software, which could run a local computer (even a small Raspberry Pi device) permitting local network access to scenes and schedules. This would provide dramatically improved response. (Not to mention, creating a method of controlling lights, when the internet is down.