The following problem:
I am having a Raspi3B+ running home assistant.
Now, I have the Pi configured to connect via WLAN. However, in my router I see two ip addresses: a LAN one and a WLAN one.

1. Can I disable the LAN IP somehow? There is no cable plugged into the ethernet port, yet it shows it as online?
2. The WLAN ip changes every time I reboot the pi. Should I set it to static on the router, or should that be done on the pi itself - if so, where?

I basically want the Pi to only show up on my router with one IP address that always stays the same.