Thermostats and cameras don’t print, so putting the printer in the same IOT VLAN with client isolation won’t hurt them. You want to be able to print from devices connected to LAN and other VLANs such as Guest. Just check the appropriate boxes on the Network Settings page. For example, check all of the boxes corresponding to the IOT VLAN column under the VLAN section. This way, devices connected to VLANs other than the IOT VLAN will be able to initiate communication with devices on the IOT VLAN. But devices on the IOT VLAN can’t initiate communication with other devices, nor can they talk to each other.
You may want to enable mDNS to help your computers find the printer.