Assuming you are asking about Google WiFi units, where the mesh secondary / extender units have Ethernet ports, then yes – you can connect nearby devices to them using either of those Ethernet ports.
The primary / router unit also has two ports, but the WAN port will be the one connected to your internet service. The other "LAN" port can be used to connect Ethernet devices, including things like Ethernet switches to make more ports available.
Thanks for the help, MichaelP.
I just wanted to jump in real fast to see if you saw MichaleP's reply and to see if you still needed some help on this or if you were able to get it sorted out. If you are still needing some help, just let us know and we'll be happy to continue helping.