Ah, that explains the "new" in the name. You can remove "plugins\calibrecompanion.koplugin" if you wish. I will mark is as obsolete, to disable it from menus even when it is there.
About the network: port forwarding is something you do between your public IP and some IP behind the NAT. Is not applicable here.
Even with a wifi extender you should be able to ping the computer that runs calibre from everywhere in your local network, including your kobo.
You can test if you're able to ping from your kobo using the terminal plugin and typing
Code:
ping -c1 ip_of_calibre
If you're able to ping the computer then use manual address/port and set the address accordly. Leave the port as default (9090) IIRC.
If you're not able to ping the computer from your Kobo the calibre plugin won't work.