You are using the device in a way that it is not meant to be used so that is really user-error, as you should not be regularly be turning on an off products that are Zigbee Router devices. You could add some more Zigbee Router devices to possibly allieveioate the problem a little, but that alone is not a proper full solution, see → Zigbee networks: how to guide for avoiding interference + optimize using Zigbee Router devices (repeaters/extenders) to get a stable network with best possible range and coverage
Zigbee Router devices should always be powered/connected, so a proper solution would instead be to either replace the switch with a smart switch that works in “detached mode” (so it does not cut power to the lights) or replace the lights with model(s) that does not act like a Zigbee Router devices, like for the example lightbulbs from Sengled → Mains powered Zigbee devices that aren't routers