Fantastic question. There is so much IOT garbage out there that someone might slip into my network, what can I do to easily detect it?
I was aghast when my partner connected a pet watering bowl to the WiFi.
It's been some time since I ran this myself but I used to have an openwrt router sit behind my ISP modem/router (it was one unit).
Multiple times I caught unexpected traffic and was able to block it piecewise including a lightbulb(!) that was sending mb packets of god knows what home.
If they were ethernet based I reckon some smart VLAN capable switches would be nice even at home to keep them out of each others business.
I moved home a few years ago and now I'm back with the ISP router and do often feel a little in the dark about what my network is doing!
I suggest you just firewall it away from your important machines and then don't worry about it.
My most worrisome IoT device I have on my network is a digital picture frame my wife connected, but I was surprised the company routinely updates it even though it's on Android 6 (!).
https://support.frameo.com/hc/en-us/articles/23433637149842-...