The courts cannot be fixed any more than government can.

The native american indians were far more advanced from a societal standpoint than we are today.

The whole concept of government started in babylon and sumer was a major step backwards for humanity.

The ancient Hebrews had judges.
They became covetous of foreign nations and whined that they wanted a king too, so God gave them Saul.
Saul was supposed to eliminate all the demonic giants but he didn't do what God said.
That's when God took away Saul's power and made David king.
But before Saul when the people had judges, they used God as their guidance, consulting the ephod's ummim and thurmin (stones) to discern what God would have them do.
It was a sort of governance relying on God.
When the people rejected God's governance in lieu of a human one, is when their internal troubles began.
And I suppose the nations whose systems they coveted
were probably those you mention, of the Sumerians

As for native Americans, their culture doesn't go back as far as we are misled to believe. It's much more recent. The various peoples who populated the Americas would have had to come here after The Flood. Genetic, linguistic, cultural, culinary, religious, and archaeological evidence shows East Asian, Middle Eastern, Indian, African (Egypt) and Nordic blood depending on the tribe. (The Mandans were mixed with Nordic and also possibly some northeastern woodland tribes in Canada).
These people were not perfect either and warred with each other, sometimes visciously, and frequently kidnapped and enslaved the children of their enemies. Sacagawea herself had been kidnapped and raised by the Hidatsa even though she was Shoshone. That was a much better fate than being killed or scalped alive.
You can't put all the various American tribes under one umbrella, as they were a diverse mix and some were peaceful and others not
Our original system was influenced by Algonquin speakers