I believe puberty blockers should still absolutely exist as an option for wary parents, unsure kids, if someone (the parents, child, or doctor) is in some doubt or as a safety net.
However, in general, if a doctor can verify that a child that openly identifies and considers themselves genuinely trans is, indeed, gender dysphoric/gender incongruent, especially if they've known this for multiple years without any presence of doubt, the child should be given HRT at around the age when they and their peers would be going through puberty. Not puberty blockers - but blocking their natal hormones AND giving them the hormones of their target sex.
A giant array of research supports that A) children know their gender as little as 3-5 years old, B) almost all children that go on puberty blockers go on to start HRT and very few go back on it (and those who would be unsure or might fear they would regret, I say, can go on puberty blockers instead of HRT) and C) the vast majority of detransition is from external pressure, bullying, budget reasons or coercion, and rates of regret are very small and rare.
Yes, there will be children who will detransition (which is completely fine - go ahead). Yes, a very small amount of children will have gone on HRT long enough before detransitioning that they will have some permanent effects of the wrong puberty.
However - millions of trans people already have gone through with this - a wrong puberty, sometimes its entire length or just a portion of it, that leaves them permanently physically and mentally scarred, sometimes to the point they will never pass without surgical intervention, if not worse.
My proposal would have a few cis kids go through something like this (though likely to a lesser extent), and much MUCH more trans kids who will never have had to. From a purely utilitarian perspective, this is a positive change. In my mind (and that's why this is apparently a 'hot take'): a trans person and a cis person going through the wrong puberty is largely equivalent, and one is not much worse than the other.
If trans children going thru their preferred puberty at the same time as their peers were normalised; those children would be growing alongside their peers - they wouldn't feel like outcasts, nor would they look differently from other kids. They'd just go through as normal a childhood and puberty as all the other kids - to the point they may have very little if anything to relate to with the rest of the trans community, which frankly, in my book is a win. It'd decrease bullying and allow them to live more like everyone else, like normal people.
Puberty blockers are generally fine if used for short periods, but if you were to stay on puberty blockers from onset until 18 - that's 7-10 years - puberty blockers can have detrimental effects. HRT, however, is just fully bioidentical and functions very similarly to regular 'natal' puberty. There wouldn't be side effects such as worse bone health/strength or risks of certain diseases.
A lot of people arguing against this will only keep the health and sanity of cis people in mind - this overwhelmingly comes at the expense, the suffering, and to the detriment of much more trans people comparatively. Trans people are people too, and their feelings and suffering matter just as much; treating the true positives properly is necessary even if a few false positives will be caught in the crossfire.
And no, knowing your gender is not in any way equivalent to e.g. thinking you're a unicorn, getting stupid tattoos, drinking and driving, imagining yourself as a firefighter, jumping off the roof, general hypochondria, or any other kinds of make-believe and play. I believe that gender and its self-identification is simply completely fundamentally different, and unique. Those children who will be fully informed on the effects and results of transitioning to a gender they prefer, and after plenty of counselling, decide it is the right decision for them - will overwhelmingly know themselves better and come to the correct conclusion.