@atpfm @siracusa I had an issue with list performance with my bookmarks app iirc around 5000 core data items. Logic like if statements in lists. I was able to fix it by architecting something that, imo is less than ideal but not awful but for the most obsessive people, 20k bookmarks should be fine.

This is iOS though, even on mac it’s designed for iPad. I don't know if designed for iPad lists are the same as native mac.