You charge all of the cells in a battery in ()parallel(?), so unless your input power is limited by something,
The correct word would be simultaneously. As plenty of them are chained in serials, and do not charge parallel.
charge time is dominated by how long it takes a single cell to go from empty to full. if one wants to nitpick, that is correct.
However the battery is full when the amount of nominal charge came from the plug into the battery. Ooops.
So a smaller battery charges much faster, as the amount of energy to put into it, is much smaller.
Hence: the trend to smaller lighter batteries, that in turn support slightly lighter engines/brakes and an over all frame, and in the end lead to just minimal range loss, but charge in half the time than the previous battery generation. With similar driving performance as in speed, reliability etc.
You morons are not even utterly uneducated how stuff works, hence your stupid idea about "all cells charge in parallel" - you are also completely out of the loop how stuff works on the other side of the planet.