>> Currency interventions never work

Where did you learn that? It doesn't reflect the structural volumes present. Central banks make interventions all the time in line with little stabilisation programs. Those are almost always deemed success.

Maybe you deduced it by yourself? If so, fx is weird despite traditionally being seen as the simplest area in finance. E.g. It's counter-intuitive but we tend to think trade make up most FX volume globally. It's in the area of less than 3%. The majority by far is speculative and hedging.

The other trap is fx volume, people assume the know what volume is but then they learn expressions of fx volume is almost always actually tick volume.