The two differences you listed improve traffic flow and safety massively!
Driver education is often more strict depending on country (I’m thinking Scandinavian countries and Germany), unsurprisingly this makes a big difference.
Traveling faster is a bit of a moot point. If people drive faster and rate of incidents and road toll are lower, surely that proves that travel speed isn’t the problem in the US.
But really, the drink driving culture in America is terrifying. The state of Texas has a similar population to Australia (where I’m from), 9,560 people died on the road in Q1 2022 in texas. Australia had just under 2000 FOR THE WHOLE YEAR! Both places have similar speed limits that are considerably slower than Europe, so I don’t think it would be honest to try and say the low speed limits cause deaths. My best guess would be that drink driving is enforced at 0.05 in Australia compared to 0.08 in Texas. On top of this, Texas only enforces if officers have a cause for lawful detainment, which is a high threshold to cross compared to random breath tests common where I’m from.