Nothing
While China says they want to go there, as soon as they go there and look at the infrastructure, it will all fall apart.
They don't want to invest 50 billion to build roads and mines to maybe get access to the resources.
Clans rule Afghanistan and what we call the Taliban are clans and without the US as the big enemy to unite them, they will have many infights for power.
There is not even close the stability for long-term investments. Without that, nothing will happen. The graveyard of empires will stay the graveyard of empires at the end of the world.
This is also why the whole concept of "Nation Building" doesn't work in places like Afghanistan.
People often bring up the successes of the idea with places like post-WW2 Germany and Japan. But the reality is the comparison is fundamentally flawed because the nations, peoples and especially cultures are nothing alike.
Both Germany and Japan for the most part were/are homogenous cultures and have had fully functioning stable governments over long periods of time. They also have shared identities and values across their own individual cultures. Not to mention after the war, both countries were literally nothing but embers and rubble that could be literally rebuilt from the ground up.
Afghanistan, once again, is a country that has for the most part through history been Tribally run. Factions and identities are a mishmash of different harsh religious ideologies. Most of which do not have shared identities or values (even if we in the West might think they do). Afghanistan itself is also harsh terrain with not much capability to quickly and efficiently build infrastructure.
Basically, it's a chaotic place, and could only be brought to heel by a power willing to use whatever means necessary to rule over it. So the idea that it could be achieved through "nation building" was a delusion from the start. China may likely try to do something with them to acquire the resources, but I agree that it won't be as easy as some might think. As has been shown, the people in charge of Afghanistan can not be trusted, and bribing them will only go so far (and usually they'll be tray you and take the money).
Even if a group is "in charge", it also seems like that control is very shoddy. Local tribes and groups will likely just do their own thing even if a Taliban commander in Kabul says otherwise.