That's nurse helpers, not nurses. Big difference. A nurse helper has no education whatever and gets more or less minimum wage. A nurse has a degree.
In Bumrungrad, as in most hospitals here, they wear different uniforms.
2 years ago, at the height of covid lockdowns, Bumrungrad didn't fire any staff. But there were no more medical tourists (Arabs etc). So a lot of staff had their working hours and their salaries cut considerably.
Maybe that explains your impression.