An excellent rider to the KIDS act would be to mandate the installation of age (that is, identity) verification to all firearms in order to disable the safety.
Lock those out too unless you can provide digital ID (and a high enough social credit score) each time you attempt to start them.
It's worth noting OP's proposed technology is impossibly far from existing in practice. Importantly, there are at least half a billion citizen-owned firearms in the USA without this theoretical technology, already. Therefore we should focus on something more effective. Such as better mental health treatment, bullying prevention, gang prevention, or any other precursors to violent behavior.
Though I think it's worth noting that age verification _without_ identity verification is basically as impracticable, and arguably more dangerous.
To stay consistent with my point though, if we mandate that everyone must ID verify to access the internet, I think it's just as reasonable we mandate that all such antiques be forcibly modernized with some sort of 5G-connected ID scanner. For the children of course.