Open the article. The byline on the article is "Remote working really could make workers happier, study finds".
Well, that's interesting, within four words we went from "are happier" to "could make workers happier". That's weird. Oh well let's continue on.
Let's go ahead and take a look at their evidence for their (now ambiguous) claim.
The data is .. a self survey of 4,000 people on what they thought about remote work, of which 2,600 of the respondents didn't even work remotely.
No actual data or measurements about whether the 1,400 remote workers actually were happier, or actually were more productive. Not a single piece of data or analysis anywhere. No, literally just a survey of what a collection of workers say they think about remote work.
Man, that's a real nail in the coffin there. Mark 'em boys, remote work makes workers happier!