can I connect my pc with wifi to the AR300M only or is a cable connection (lan-port) also possible? If yes, what are the settings for this?
I want to use openvpn and I hope a cable connection is faster than the wifi-connection.
Thank you in advance!
No and yes (ie. you can connect by both wifi and cable).
Regarding settings, you didn’t look very hard: Overview - GL.iNet Docs
You can connect from both wifi and LAN. Openvpn doesn’t works faster via LAN because the wifi speed is faster enough than the VPN speed limit.