Here is the quick/easy method. Remove the lens. Using a black permanent marker, dab a black dot on every 4th LED to reduce the over-all light output. If it is still too bright, dab every other one. The dab will reduce, not eliminate the light output, so you might find yourself dabbing every LED, especially where the fixtures are in tight quarters.
The proper solution would be to disable LED circuits which would also save on battery energy.
I did the dab on my Saturn Sky interior illumination project when converting from incandescent to LED. The LEDs for the switches and controls were otherwise blinding. So many incandescent bulbs were burnt out so performing the conversion was an opportunity at hand.

