What's the regret rate for gender affirming care?

Yet they don't revoke the use of puberty blockers for cis children with precocious puberty, they only are concerned about the lack of data for trans kids - it's motivated by transphobia, not actual clinical concerns.

Trans kids aren't having poor outcomes from gender affirming care, quite the opposite actually - and the "we don't have enough data" argument is a false concern used to plausibly deny a more than sufficiently demonstrated clinically safe and effective treatment.

EDIT: might be interested in reading: https://whatweknow.inequality.cornell.edu/topics/lgbt-equality/what-does-the-scholarly-research-say-about-the-well-being-of-transgender-people/

We should be clear, the medical establishment is not woke (quite the contrary, actually) nor is every single major medical association recommending gender affirming care for trans youth on ideological grounds or because they have been forced to by some LGBT+ lobbying, but because the evidence we have points to that care being life saving and effective while also being low risk and in the case of puberty blockers even reversible.

EDIT2: you should also know the Cass Review has been found to be biased in its recommendations, e.g. this demand for high evidence in the case of trans care but not other areas of care have been pointed out as motivated by prejudice, might be worth reading more about the criticisms of the Cass Review:

https://en.wikipedia.org/wiki/Cass_Review#Reception_by_academics_and_researchers

Several scholars and organisations have criticised the Cass Review's conclusions and the evidence base used to support them. Researchers Cal Horton and Ruth Pearce have said of the Cass Review, "its most controversial recommendations are based on prejudice rather than evidence". Cal Horton criticised the Interim Report and other documents for prioritising research on aetiology of trans identities, saying: "Research into the causation of trans identities has a pathologized history, running parallel to efforts to prevent or cure transness." Cal Horton also criticised the Interim Report's support of exploratory therapy and its use of the terminology of "desistance".

Various scholars also criticised the emphasis on high and moderate quality evidence, saying that paediatric care often relies on low quality evidence in other areas; that in downgrading qualitative research, the patient voice was minimised; and that the highest quality evidence (such as from randomised controlled trials) may be difficult or unethical to obtain in this area.

Forcing trans kids to undergo the wrong puberty under the demands double-blind trials is as wrong as forcing a cis child to undergo the wrong puberty for the same purpose (like David Reimer was forced to), it's an unreasonable expectation given the clinical context of the treatment being so low risk and the outcomes being so positive.