If everybody improves their looks, the net effect will be zero. It's also not clear what parts of "looks" actually have an effect. It's also not clear what effect GLP-1 has on other elements that might make someone more employable.

The study itself is certainly not conclusive. The control group were women who wanted to take GLP-1, but didn't. That can indicate all kinds of status/class differences. The study also seems to have been a fishing expedition, and is based on self-reports, so it's tentative at best. I wouldn't recommend taking GLP-1 for a job interview based on this article.