Will I have to reset up the Apple TV if I unplugged power cord or HDMI cord?

No, it won't be the same. Unplugging the power cord will cause the ATV to power off. Unplugging the HDMI cable will not cause the the ATV to power off.

You will not lose any settings by unplugging either (or both) cords.

Hello,

If you unplug Apple TV’s power lead then Apple TV will be powered off. When you reconnect Apple TV’s power lead then it will start back up exactly how you had it.

Hello,

Apple TV will not power down or restart if HDMI is disconnected.