Orbi 870 Print on both Home & Guest network

Alas, Netgear does not allow this.  Devices connected to the Guest WiFi network cannot communicate with the primary network and cannot communicate with any other device on the Guest WiFi network.  The only thing they can do is communicate with the internet.  So, even if the printer is connected to the Guest WiFi SSID, no devices can print to it.

The only way to permit a visitor (i.e. "guest") to access a printer is to let them connect to the primary network, either with a 'wired' connection or to the Primary or IoT WiFi network.

Netgear created the IoT WiFi network so that customers who have devices with poorly written smartphone apps can get those devices connected to their WiFi system by temporarily turning off the 5G WiFi signal so that the only WiFi available on the IoT SSID was 2.4G.  After the device has been connected successfully, then the user can enable the 5G WiFi radio again and operate normally.  I have zero devices that could not be connected to the primary WiFi network, and thus have no need for the IoT network

If the goal is to allow visitors to print without sharing the primary WiFi password with them, this would work:

• Do not place any devices on the IoT network.
• When visitors arrive, tell them the SSID/password of the IoT network.
• Devices connected to the IoT network are able to access printers (actually they can access everything on the primary network)
• When they leave, change the password to the IoT network.

(if the IoT network is already loaded with devices, it's "too late" for this strategy.  sorry.)