Should use one VLAN per device. I think manufacturers will start using their own mesh networks. If your neighbors have a Vizio TV, your vizio TV will use their connection, same for Samsung, etc. If you have an open guest network, these devices will use it automatically.

The Brother printer I have attempts to hit some static IP in Japan for firmware updates, unencrypted http. So while on some OSes, you can use it without installing a drive, on MacOS, your desktop will automatically download the vendor's software indirectly from Apple. That is why installing printers is a separate permission as it updates system level components.

The only immediate solution I see to this is to have a protocol level firewall say running on an RPi that firewalls the printer off and intermediates all communication between the devices on the local network and the printer.