Actually, there are two fantastic (and scientific) reasons for trial by combat and ordeal, that contradict your implications.
They are (a) clear demonstration to the community of the veracity of one’s word, (b) warranty of one’s word with one’s life, and (c) an honorable death in the case of one’s guilt.
Trial by ordeal is a form of voluntary submission to a torture to the degree that the community no longer holds doubt.
“One’s word” in the germanic tradition, certainly back to the Yamnaya was one’s life. And the means of transitioning into male adulthood was The Oath. And the Oath was very simply, do not lie, do not steal, and do show cowardice in battle.
Simple rules produce complex outcomes.
The trust of our ancient peoples has been undermined by familiarity with abrahamic modernity.