Much of the current state of the world is coasting on things done in prior eras, and this is always the case. A country needn’t be able to build a large boat now to have built one in the past. They can send that boat around the world until someone realizes that the US guarantee of safe water ways too is something it can no longer enforce. The world behaves as if the USA were its older self, but it isn’t. Also, a large navy isn’t very useful when ships that cost more than a billion USD can be disabled by drones that cost less than ten thousand USD. As such, US ship movement in the area is limited by both Yemen and Iran.

The world before WWII was chaos. It has never been peaceful to be a human for much of our species' existence.

America was the global hegemon. Under the "rules based order", where America safeguarded international trade in exchange for having the US Dollar at the center, we had the largest period of stability the world has seen.

Now that everyone wants to displace America, we're pluging back into chaos. America is abdicating its role and turning into an isolationist power.

There's going to be an increase in war as countries try to claim territory and resources.

Piracy and blockades will come back. Trading alliances and trading blocs will form.

The world will turn into a powder keg. This time with nukes.

The vacuum left behind as America shuts itself off will create lots of power struggles. There will be a lot of trade disruption to energy, goods, and food inputs. It's also going to be incredibly violent.