N7 Bluetooth is designed to work in half duplex mode, meaning N7 can transmit or receive audio signals via Bluetooth, but not simultaneously. Therefore you should be able to use your Apple TV as the source and set N7 as the wireless DAC to your Apple TV. I have checked the specification of Apple TV, it is VT v5.0 based, but I can't find the codec list supported by the Apple TV, I assume you can connect them in AAC or SBC, lossy up to 48kHz in both cases.
I assume you have reached this Bluetooth setup page. If you want to set N7 as a wireless DAC, you should select "Bluetooth Audio Input" in N7 (the command above + Pair New Device).
When you select Bluetooth Audio Input, N7 will enter the Bluetooth DAC interface like below. You can search and select N7 from your source Bluetooth device (Apple TV in your case) and complete your connection.
In case you still can't get the N7 to playback your Apple TV content, you can remove the previous connection and start from scratch again:
- Forget the pairing of N7 in the "Paired devices" section of the mobile phone or device's Bluetooth settings (if the device/phone was previously paired with N7 via Bluetooth);
- Forget the pairing of the corresponding device/phone in the "Paired devices" section of N7's Bluetooth settings (if the device/phone was previously paired with N7 via Bluetooth);
- Tap on "Bluetooth audio input" in N7's Bluetooth settings;
- Search for N7 in the device/phone's Bluetooth settings and pair and connect to it;
- Once connected successfully, you can use N7 as the Bluetooth DAC for the device/phone.