Do you own a Nest thermostat? If so, that's what's being detected as a Nest device. Camect can't tell that it's not a camera unless you sign in. Just disable it and ignore it.
The Dahua one is more unusual, but probably similar ... We could try to help you figure out exactly what it is (and I assume you already see the IP in the UI, so you could check?), but if you're sure it's not a camera, the solution is still to go ahead and disable it and ignore it.
If you'd like more info about what devices Camect is finding on your network, you can go to home settings > devices > add camera > see all devices found on this network ... There's a search box at the top that may also be useful if you have a large number of devices.