

Easy mode: don’t connect it to internet
Slightly harder: add exceptions for bambus servers in your routers firewall so that requests to that domain are blocked
Dependent on hardware that you own and less likely to exist on basic routers: create a virtual lan for your 3d printer that does not have internet access but has intranet access, allowing you to connect between computers but not to the web (my preferred solution)
That’s similar to the isolated vlan but someone who knows more about networking than me will probably be able to explain why the vlan is superior. I would imagine it’s failsafeness, the vlan is just its own thing
The benefit of doing the domain specific firewall blocking would be if you wanted your printer to otherwise have internet access (eg to check octoprint remotely). I don’t print when I’m not home due to the risk of fire and I don’t trust opening up my printer to the web, so I don’t bother with this. Others may have different opinions on acceptable risk