How to reduce the minimum Exposure Time?

I’ve been trying to use libcamera_cpp_demo and I’ve also included the code to get the control list from the camera.
However the images are overexposed in daylight, there seems to be a lower limit of 88 microseconds. Even changing ExposureValue to -4 (and lower) and putting the torch in front of the lens is not able to reduce the Exposure time below 88 microseconds.
when I’m manually changing the ExposureTime by code to around 20 microseconds I’m able to get the better exposed images.
I feel somewhere there is a limit of a minimum 88 microseconds Exposure Time. If so how can I reduce it?

manual exposure 29 microseconds ExposureTime

auto exposure 88 microseconds ExposureTime