https://screenrant.com/smallville-biggest-changes-superman-origin-story/

While slowly transforming Clark into the comic hero, Smallville made several massive changes to the Superman mythos and the character's comic origin.

The writer of that article doesn't know his DC history very well. There was a 1960 Superboy story that revealed Luthor's origins. Here is what the article came up with for #5 in its list:

Perhaps the most obvious difference between Smallville and other Superman stories is where Lex fits into the equation. The series turned the comic book archrivals into best friends to start the series, with the expectation that they would become enemies later. In the end, that’s exactly what happened, but going in this direction marked a significant departure in the comics. Essentially, Smallville made Clark a big part of the reason Lex turned evil.

This item is off-base. In the DC origin I've mentioned, Clark & Lex originally WERE best friends. However, when Lex was working on an experiment as a young scientist, Clark (as Superboy) accidentally caused Lex's baldness and destroyed what he'd created, and that led to their becoming enemies, with Lex going into a rage -- indeed being "a big part of the reason Lex turned evil."

Synopsis of the comic book story from the Grand Comics Database:
"Young Lex and Superboy start out as friends, but after Superboy accidentally destroys Luthor's laboratory and accidentally causes Lex to lose his hair, Luthor vows revenge."