Looks like problems I experienced with Blender, by the dots, squares and color in the model displayed in Cura....
Suggest making a 2D sketch and then extrude it. Makes a better model than using too many Bool Tools operations.
Try export in Blender to OBJ file or STL file .....sometime help from little to almost good
Help more provide different views of model in Blender to maybe understand the problem more...