I did some quick research and found out that TMS export option should be very straight forward to implement. Current version export Google Map Tiles as <root_dir>/{z}/{x}/{y}.png format, and all we need to change is {y} value to make it compatible with TMS format using below formula.
{y} for TMS = (2^{z} - 1) - {y} (from Google Map Tile)
I tested this with my own Python program and confirmed that it works great.
I will be more than happy to share my code if that helps implementing TMS orthomosaic output capability.