>“We’re all familiar with the Freudian idea that if we suppress our feelings or thoughts, then these thoughts remain in our unconscious, influencing our behaviour and wellbeing perniciously,”

The article conflates thoughts and feeling.

Thoughts and emotions are not the same.

Reducing negative thoughts is standard practice.

https://en.m.wikipedia.org/wiki/Automatic_negative_thoughts

I'm not aware of any professional who recommends suppressing negative emotions.