I frequently fly with 2x 155wh batteries (for cameras) in carryon - SFO-TYO, never questioned. Have connections taped and in a ziplock or connected to a device or charger so it can not short. 200wh is not ok, must go by freight. Its IATA regulations, not tsa/faa:
https://www.iata.org/contentassets/6...um-battery.pdf

Some airports - HKG/AUH/DXB - sometimes make you show that it powers on a device. HKG about half the time they call the operating airline and ask for permission - only place that has happened, never been denied - they just like to be annoying.
If security does look at the battery, they almost always check to make sure its less than 160wh.
Travel with a printed copy of the above iata document in case there are any questions, I've had to show it a few times.