I’ll answer contrary to others and say it will be just fine, if you always use the wall switch to turn the light off and on, and just want the zigbee function for dimming or color changing.

You would want to make sure that they are off when you pair any new battery-powered zigbee sensors. (Or have another way to force which router a new battery-powered device pairs to.)

As long as you do that, and you have sufficient other routers, the mesh will be fine.

I’m using zigbee bulbs like this successfully with no issues, with Home Assistant and Zigbee2mqtt. It’s easy to create an automation in HA that triggers when the bulb turns on (which will happen when it’s powered up from the wall switch), to set brightness or color.

There’s an entire industry of commercial building architects and design teams that are installing PoE-powered lighting and other non-network devices everywhere. It’s not 2003 any more.