Guest wifi or iot network across entire network

Just picked up an MT6000 and very impressed. I have a large house and will be using multiple AP throughout the house to extend coverage. I noticed that when I put the router in AP mode, the UI drops the ability to create additional SSID. what is the official way of extending guest, iot, or any other SSID throughout the additional access points in the house?

Then you probably need a dedicated access point, which offers more flexibility in configuring and managing multiple SSIDs. In contrast to the AP mode of a router, which often has limited functionality, a dedicated access point allows the creation and customization of different SSIDs for guests, IoT devices, and other purposes.

Dear @rykr ,

As @buntspext has wisely noted, there exists an option to introduce an additional access point, colloquially known as a "Dumb Access Point." This setup, though intricate, permits the assignment of VLANs from the primary router, thereby extending your segregated networks through WiFi or LAN.

Please feel free to review this video from a YouTuber channel called OneMarcFifty:
extend a guest wifi on second access point with OpenWrt using VLANs - YouTube

May this provide clarity on the time and effort required.
Wishing you a most engaging and successful late-night troubleshooting session.