Coal power plant efficiency is less than 40%. You'd also not get 90% of the outlet on the wheels. There is also a lot of loss on the grid, but there is also on the production of fuel. The two pollute almost the same.

Burning coal however is a lot worse for the air quality.

The coal plants are not 100% efficient though. In fact they're probably in the realm of 40%

What about the billions of cells that must be produced and replaced as the scale grown unto millions and millions of cars? And all the mining of rare earth elements it requires?

That is true. I do think we should retire pure ICE cars as soon as possible. If you need to do long distances, a hybrid that could be converted might be a good intermediate solution. If you only need a car sporadically, a car sharing platform with electric cars is a good solution. These already exist in big eu cities. Ofc good and adorable public transport is nr 1.

Decreasing the amount of cars would decrease emissions short and long term more than the current shift to EV and would make shifting easier as there are just fewer to replace.

I put very minimal calculation which at least puts it around the same order and linked a report by Volvo where they try to count the whole cycle of a car with the emissions of the production and transport of used parts and fuels.

On current electricity mix, an electric car is only slightly better on a CO2 emissions. With only renewables, it can be 2x better.

But the statement that in China it's at least better than a Prius is just wrong. Until renewables take a serious share of the grid, a smaller well engineered hybrid is not worse.