That’s not what the linked story says. It says that the top case beat the market by 200% and that it was through an Nvidia position purchased 4 years ago. The Congress person in question hasn’t made a single trade in the last 3 years.
The 10th best position was 63% better than the s&p. That’s just a touch better than keeping your money in qqq.
There might be evidence of congressional insider trading but the bare numbers aren’t it. In a population of 540 people you’d probably find similar outliers to what that article outlines.