I currently use a TP-Link Archer router as my main router at home, and I’ve connected two additional sub-routers (in AP mode) via Ethernet to cover both upstairs and downstairs. The whole family’s internet access is very stable. Recently, I purchased a lot of smart home devices (cameras, smart bulbs, smart plugs, etc.). I don’t trust the security of these cheap devices and worry they could become a gateway for hackers to access my personal computer and NAS storage. Therefore, I want to add a third access point (AP) specifically for these IoT devices and occasional overnight guests. This new AP must be able to connect to the internet normally, but it must be completely prohibited from accessing any local devices on my existing network. I’ve seen people online say I need to buy a VLAN-capable switch, others say simply enabling “guest network” is enough, and some say I should plug the second router into the WAN port of the first router. What should I do to allow these external devices to get online while keeping my personal information safe?