Oh that’s good then. I think they stopped using whitelists a while ago, so if it is slotted you can probably replace it with anything. Maybe they reversed course on soldered modules then, or perhaps it only applied to some models. I looked into specs of the T16 at some point, and that one had soldered wifi module.
I fail to see why this is bad advice. Sure you could just disable the firewall on your computer on a local network. But that’s under the assumption that you can trust everything on your local network. What if it’s a laptop? Do you also trust any public networks you may connect to on the go? Having firewall both on the router and on your computer provides an additional layer of security, and I think that’s good advice in general. You can for example set it up to only allow incoming connections when connected to your home network for example.