Hello, and welcome!
I don't know anything about the various Raspberry products, but if the models have both a wired NIC and a wireless NIC, they can act as routers between a wired subnet and a WiFi subnet.
If you want to route wired Ethernet, then a single NIC does not a router make, unless you implement a
vlan(4) based infrastructure, and route via individual VLANs.
VLAN - IEEE 802.1Q - requires a central backbone device called, quite subtly, a
managed switch. Unless your switch is in this class, you'll need to use a computer with at least two NICs. Managed switches come with administration and provisioning tools, so you would know if yours was in this class.