But I don't think it's clear that the highlighted is correct. Mostly because you are asking people with dysphoria to put their related issues on hold until some magical age, and as a consequence you are also forcing them to wait to transition until the point where for most of them their body develops to a point where they will always appear as an other. And I'm talking with their clothes on.
Let's unpack this a bit. You're talking exclusively psychological pain in terms of distress over a sexed body. But there are other effects from hormone blockers and cross-sex hormones being applied during puberty.
We've covered the effects of puberty blockers, so I'll just do a quick recap. Low bone density that cannot be recovered, lack of cognitive maturation, impeded and incomplete physical development (especially sexual development), and sterility.
So let's make a massive simplifying assumption, and say that the "true trans" children you're talking about are so perfectly diagnosed that they are never given blockers, they just go straight to sex-hormone suppression and cross-sex exogenous hormonal supplements.
Let's talk about a young female who is "true trans" and identifies as a boy, and doesn't want to go through their natural female puberty. Because they're taking exogenous hormones, they will experience at least some cognitive development associated with puberty, and they won't face the problems of osteopenia. On the other hand, without the estrogen/progesterone cycle... they won't grow breasts and develop milk-producing glands, they won't experience menarche and won't be able to release eggs, their hips won't widen and shift position. The testosterone will produce a greater muscle density in more typically masculine locations on the body... and will also destroy eggs. Testosterone also causes vaginal atrophy. The lack of estrogen also means that the clitoris and vaginal tract won't achieve adult sensitivity. So while the female may cosmetically appear more masculine, they also will be extremely likely to be sterile as well as unable to experience sexual pleasure.
So let's talk about a young male who is "true trans", in the same basic scenario. The lack of testosterone prevents the jawline from becoming heavier, prevents the growth of facial and body hair, and reduces muscle density. It also, by the way, prevents the descension of the testes and the elongation of the penis, and prevents the onset of sperm production and prostate function. The estrogen will result in fat deposits in more traditionally feminine locations, including the breast area... but it won't result in the development of milk-producing glands to the degree that a female would grow. And again, without their body's natural hormones, they will not achieve sexual maturity, and will most likely be both sterile and unable to experience sexual pleasure.
All in all, we're talking about the cosmetic advantage of looking more like the opposite sex... but at the price of fertility and sexual pleasure. I think you may be underestimating the importance of sexual pleasure in the average human. Some people choose celibacy and a life without masturbation... but they're quite rare.
I'm not convinced that it's in the best interest of the child to indulge their desire for physical appearance while depriving them of physical pleasure. How can even the most "true trans" child consent to that trade-off, when they don't know what it is they're sacrificing?