You lightly de-myelinate their thalamus, somehow- maybe their whole brain, then pharmacologically suppress re-myelination. The second part is feasible. The first part is still science fiction; the best anyone can manage is total, uncontrolled de-myelination, which will kill you, if you're lucky.
What does your model predict about the impact of precocious puberty, and how does that compare to the available data?
What does your model say about the impact of delaying puberty, and how does that compare to the data on adolescents who use puberty blockers and then undergo puberty at a later age than most?
When trans people medically swap out one of the standard sets of hormones for the other in adulthood, it's often referred to as "second puberty", because there's a lot of similarity to what happens when the endogenous puberty hormones first show up. What does your model predict should cognitively result from doing puberty again, and how does that compare to the available data? (for this, definitely consider trans people who choose not to use hormones as a control group)
The prediction is that precocious puberty should correlate to a lower IB. There doesn't seem to be any real study into IQ scores for children experiencing precocious puberty. I only seem to be able to find a study by John Money claiming girls show a higher "Verbal IQ" (Which, if you know anything about John Money, you know is worth less than nothing), another in 1984 with a sample size of 103 girls (52 precocious/51 normal) agreeing with John, and a third one in 2016 with a sample of 30 (15 precocious, 15 normal) finding the precocious have an IQ of 94.
Long story short: Nobody tested their IQs, and what little they did test doesn't actually map to IB.
The IB model doesn't account for hormones at all. I don't know that myelination pace is at all affected by them. Affecting hormone levels downstream with drugs should have no impact at all on the actual process of maturation. That said, as the brain myelinates, critical developmental windows might be missed. The current generation of children would be the guinea pigs to find out just what part of the experience of Puberty at its natural age is essential for development.
I put together a model explaining the link between IQ and the onset of puberty. Ideas only thrive when they're attacked, and I was told this was the kind of place that could manage it.
The core idea is that slowing myelination in the brain extends its plasticity window and encourages more robust and efficient thalamo-cortical integration. By considering latency, the model naturally gives rise to Deco and Kringelbach's Turbulence model by turning cognition into a latency/energy optimization problem.
From what I can tell, it fits a surprising amount of cross-disciplinary evidence, but I need counter-examples more than anything.