What would improve mental health in secondary schools is a reduction of tests, targets, assessments, comparisons and an overall emphasis on data that forces SLTs to see students as 'data' and loses sight of the whole child. This would entail massive changes within central government.
A focus on the joy of learning in the here and now, rather than talking about GCSEs the moment children step into Y7.
A sensible, research and educationalist led curriculum that is broad, varied and flexible.
Exam formats that are flexible, student-centred and less cut throat.
Proper funding so that there are sufficient qualified teaching and support staff, who feel valued and respected.
Sufficient funds to resource the above, and provide test books, mend leaky roofs, fix broken boilers etc.
A stop to the endless tinkering with the curriculum, exam formats etc and space for proper thought and reflection.
A move away from some children being seen as 'more valuable' to the school because of their likely exam attainment, as the cost of others being seen as less valuable.
Properly resourced and staffed CAMHS teams that are able to offer prompt and if necessary long term interventions.
The list goes on and on and on.
Learning to breath in a particular way doesn't really cut the mustard, given the state of play at the moment.