Physics engines are rarely deterministic, which means most of these games use what you would call the "animation deciding results"
It is very rare that it works the other way around contrary to what others have commented it is non trivial to make weighted deterministic random in this manner
While technically possible, only very specialised games with reasons good enough to budget the programming required will go the route you describe as "result calculated before the animation"
I love the videos on it, and fist off I liked the site too, but they have been enshittifying it pretty hard lately