Other direct quote:

Some officials briefed on the intelligence said that it was relatively weak and that the Energy Department’s conclusion was made with “low confidence”

An article from a well-respected journal: https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(24)00206-4/fulltext.

It really seems like the evidence points towards natural origins. And the article you linked doesn’t actually have the evidence, it only waves toward the existence of classified intelligence.