The day-to-day pressure didn't affect Trump very much physically and mentally but he's the type that thrives under pressure.
Biden on the other hand will stumble around like the old fool he is. As Obama said, "never underestimate Joe's ability to eff things up." And that was said back when Joe was still occasionally coherent.
Just the pressure of being around folks who are stressed out will push Joe over the edge.
That said, someone is going to make a killing by publishing a book of Joe-isms. A nice graphic hardbacked coffee table book with illustrated drawings of "dog-faced pony soldiers and Corn-Pop..."