When I export using the settings shown in the image, the export is fast but the "Add to the Catalog" action is EXTREMELY SLOW. You can't really do anything else in LR while the background add to catalog is happening because it resets everything after each image is added so you can't scroll or anything and when you are exporting 75-100 images it TAKES FOREVER and kills the entire efficiency of the process.
My setup is very similar to OP in that I have an export preset to rename, resize and place files in a sub folder of original folder and then add them to the catalog. Again, the export happens very quickly but the last part of adding the exported images back to the catalog is excruciatingly slow. This has been a problem for a while but I really would like to get it resolved. Any help would be greatly appreciated!
I've struggled with this problem for at least a year. So frustrating! It's much faster to export without ticking "add to catalog," and then importing. That just shouldn't be! You'd think that users would be howling about this, but I've only seen a few complaints. That could be because most users don't tick the "add to catalog" box (which would surprise me), but also could be caused by something unusual in one's local configuration. But I can't think of a setting that might cause this! Any ideas?