The quality of an orthomosaic product generated from drone images using orthomapping in ArcGIS Pro is poorer compared to the result generated by Drone2Map for ArcGIS.
The issue cannot be reproduced using appropriate parameters. If you take all default parameters, it will produce a good orthomosaic. An finer resolution of DTM can make the orthomosaic better. The following orthomosaic is orthorectified with a 1 meter DTM generated from the images.