This is correct - Top Gear did a test years ago where they put a very good sim racer in a real race car (https://www.topgear.com/car-news/gaming/geek-rebooted).

TLDR: he did OK, but was nowhere up to the physical challenge of staying in that car for full race distance. And, for the record, that car won't be on the same planet as an F1 car in terms of physical forces put on a driver.

I've heard that nascar drivers can lose up to 8 pounds in sweat over the course of a race. The constant forces on your body for that long have to take a physical toll on your body.

An hour of karting did that to me...