There seems to be three types of needed states or state-like structures.
Firstly, we need small or federated states, where the local population and its authorities have more freedoms on the regional level.
Secondly, we need continental federal states or continental unions of states in order to ensure peace and stability.
Finally, we need a world-wide confederation of all states in order to solve global problems like climate change or international terrorism.*

*To be clear, I refute any world government. Such a government would either be democratic or tyrannical. The former would want to search a (quasi) impossible political consensus for billions and not millions of citizens. The latter would not allow any free governance, because the tyrant’s government would be the only one.
Julien Sita, July 29th 2021.