While the original study was published in a peer-reviewed journal, the claims in the article you linked are exaggerated/misleading. Later in the article you linked, one of the study authors clarified that the study was done on viruses and it's not known whether humans will experience the same health benefits: “The virus continuously replicates, increasing in numbers at the entry sites such as nose or mouth, and it can move fast to the lung. That’s when we see severe disease. So, drinking or gargling with tea alone will not protect your lungs.” Also, the teas had the most effect when concentrated to a level that we don't normally drink and when drank ASAP after infection.
To be fair, the article does mention these caveats, but they're sort of buried near the bottom and it's easy to be misled by phrases like "tea may stop COVID in its tracks by reducing viral load upon contact" and even the title "How Drinking Tea May Inactivate COVID". The benefits for humans drinking normal tea are exaggerated and not totally clear at this point.