@snajperist it helps to understand how most of these aspects work in the first place.
With the exception of the no-fly icon I can attempt to explain the rest.
Heart Rate
Suunto is known to not have the most reliable OHR sensors, but even if it does it’s fairly easy to pick up the wrong signals. Chest straps are much better but not foolproof either. In that case the most reliable HR sensor is the pulse check.
Altitude
Automatic correction uses GPS which is not very accurate for vertical positioning. Calibrate manually to known elevation.
Sleep
According to the manual, “Suunto Ocean tracks your sleep based on accelerometer data.” If you have been very idle during your TV session it is possible that the 30-minute activity could be treated as an awake period. Setting a sleep schedule on the watch that matches your own should anecdotally improve tracking accuracy.
Steps
Again, estimation based on accelerometer data. Suunto has a tendency to overshoot in the past but recent software seems to try make this more realistic.
Compass
Any device is subject to magnetic interference so ideally you would want it calibrated before every serious use case.
Shutdown
I agree with you on this.