While your WiiM device might well be connected to Ethernet, the WiiM Home app on your phone or tablet won’t be, and it uses your wifi network to communicate with the WiiM device.
Unless CNN and NPR actually have radio stations you can listen to and those have a published url rather than just a website, then I’d say no, you can’t just access them in the manner you think.
I fear you have perhaps misunderstood the purpose of a streamer/amp like the WiiM devices - they’re not a replacement for a pc browser or app in the manner you describe. Best you can do as I say above, is to wirelessly cast audio from your tablet/phone either from a browser or app to a WiiM device, which won’t involve presets nor the WiiM remote.