The only devices on wifi should be cell phones and laptops if they can't be plugged in. Everything else, including TVs, should be ethernet.
When I moved into my last house with roommates their network was gaaarbage cuz everything was running off the same router. The 2.4ghz congestion slowed the 5ghz connections because the router was having to deal with so much 2.4ghz noise.
A good way of thinking about it is that every 2.4ghz device you add onto a network will slow all the other devices by a small amount. This compounds as you add more devices. So those smart lights? Yeaaahh
