It’s 10% smaller. Size of battery has no affect on charging speeds tho. And I saw a test that the 11 Pro beat out the 12 pro by one hour and some change. So we should all see less battery time then the 11 series.
The size of the battery definitely affects the charging speed. If you are going from 0% to 100% on a 2000mWh battery and 0% to 100% on a 4000mWh battery with the same 5W charger than the larger battery will take twice as long to charge.