I agree Neurology is in its infancy. There are many tests and a litany of names of conditions, signs and symptoms. However there are but a few blunt treatments that may or may not work.
I agree that the best course of action is create the conditions that allow the body to heal itself with a strategy something like this.

1. Good healthy diet. Consider intermittent fasting. Appropriate Supplements.

2. Adopting a positive attitude, personal responsibility and mindset of self treatment and recovery.

3. Exercise, rest and recovery (wherever possible.) Setting up the whole day for a great sleep.

4. Engaging the parasympathetic nervous system, as you say by remaining calm, by meditation, breathing exercises etc. The brain's function is to keep us safe, however sometimes it overdoes that and makes us anxious when anxiety is not appropriate. The first step is to take a moment and realise, at times of anxiety, that the brain can sometimes over react in its quest to keep us safe. A few belly breaths that engages the diaphragm and therefore engages the calming parasympathetic nervous system (automatically) is a good strategy.

5. Maintaining a circle of friends and social interaction.