Help optimizing my Router 12 for smart home devices

I just upgraded to the Router 12 model because I needed better coverage for my whole house. I have a lot of smart devices now, including dozens of bulbs, cameras, and thermostats, and I'm noticing some intermittent dropouts. I've tried changing the channel and doing a full factory reset, but the issue persists, especially at night. Is there a specific QoS setting or firmware update I should be looking into to handle this density of connected IoT gadgets? Any advice from people who run large smart homes would be greatly appreciated.