@treebeard as far as i know, waydroid cannot use directly a wifi connection. Since it's an emulator, it creates a virtual network.
However, you can run this command to have a "fake wifi" for those apps:
waydroid prop set persist.waydroid.fake_wifi (string, 91 character limit) Comma separated list of package names for which the system will always appear as if connected to wifi. Supports wildcards with . For example, set this to "com.gameloft." to match all games by Gameloft
For whatsapp, when it waits for wifi connection to restore / backup media, this works like a charm. It can take a while until it activates the fake wifi.
But for some apps, to cast to the tv for example, i have issues since the fake wifi doesn't connect to a network, so the app won't find a tv to cast.
Hope it helps.