My plan is exclusive to carrier’s data only SIMs, the SIM card has a phone number but cannot receive calls. I don’t think I can call even emergency services. Using a 2nd SIM with no plan to receive calls and the outgoing calls are always over WhatsApp. The point is if you look for data only SIMs you may find cheaper plans.
A Linux PC connected to the printer can advertise it to LAN with CUPS.