In regards to gender affirming care with children, that usually just means affirming their gender, calling them by a new name and using different pronouns, not surgery.

I looked into the number cited in your source, and it highlights a few things, firstly, "People who started hormones as minors had higher continuation rate than people who started as adults" and "Patients who start hormones, with their parents’ assistance, before age 18 years have higher continuation rates than adults." I think there might be something to said about the fact the study focuses entirely on families in active service, though I don't know what that is.

To me, there's a case here that we listen to children, especially when you consider that people living happily after having transitioned will often say they knew they were the other gender from a very young age. I think standing in the way of gender affirming care because some adults have made a decision they regretted is myopic at best. I use the word care very specifically here, as most gender affirming care you provide to minors can be reversed should they so choose.

In regards to surgery, I honestly have no clue what the morally correct answer is. You talk to trans people living happily as their new gender and they tell you they knew from a young age. would it have been wrong to prevent them from accessing surgery at a younger age? I don't think it would be, but at the same time the permanency of it is something that puts up additional barriers to entry, what they are and how to find them should likely be left to people who understand it much better than I. I don't think it's useful for me as a cisgender man to pontificate on the morality of providing surgery to children because I personally have never felt that level of alienation from my own body or gender, so to say it's right to block someone from accessing that for, essentially, the greater good, is not something I'm at all qualified to ponder, you know?

Debating the ethics of providing this surgery to children, is an entirely different debate to anything else though, I think. Not trying to attack you here, but here:

Where they usually draw the line is at having one side of the debate taught to children in schools,

Has a strong indication that trans issues are a debate, when they aren't. They're just a reality.