The good doctors don't always keep up with the latest studies. They are busy people with many desperate and unhappy patients who provide a steady stream into and out of their crowded offices, especially after COVID and with RSV now coming more to the fore.

Caffeine, like alcohol (but not really, since alcohol is ALWAYS a toxin) can actually be helpful to a stressed heart. The following study is brand new and does a good job explaining that caffeine is unlikely to be your culprit. It still might be better for some to refrain from caffeine, but most of us can still use moderate amounts with impunity:
https://www.webmd.com/heart-disease/atrial-fibrillation/coffee-atrial-fibrillation-link
https://www.heart.org/en/news/2024/03/01/can-people-with-an-irregular-heartbeat-drink-coffee