On your first point, does the evidence show that taking puberty blockers makes you more socially isolated? I have seen no evidence of that at all, and instead there's a mountain of evidence that social transition and puberty blockers lower suicidality in trans kids and increase mental health outcomes.
We've been using puberty blockers, not just for trans kids but for precocious puberty for decades and have more than enough long term evidence of their effectiveness and safety. No drug or procedure is without risk, but why is that only a problem for this issue? Are you also against kids getting chemo? I mean, they certainly don't fully understand the risks of chemo do they?
The question of consent and knowledge of risk is a red herring. Kids can't consent to any medical procedures or sex because we've defined consent that way. But consent from the patient is not always needed for medical procedures, especially when the patient is unable to give consent. Should coma patients still get care that has risks? They can't consent right?
Consent is given by the parents and the medical professionals who have the authority to make those decisions. You can ask the kid, and they usually do, but their consent does not matter. That's how all medical procedures work with kids.
In reality, your statements lay bare a bias, which is why you're getting downvoted. You only seem to care about risks and consent for this specific highly-politicized topic and not medical procedures broadly. Because this is not about a broad critique of consent, it's about trying to excuse your uncomfortablity with this one subject and trying to justify it in any way you can.
You don't have to understand it, and you don't have to agree with it, but you should at least recognize why the majority of major medical institutions make the recommendations they do. And, shockingly, it's not because they somehow forgot it was involving kids, it's because they know a little more about the topic and nuances than you do.