Beachballing, duplicates in Apple Contacts app
Any edits or deletion of individual contacts causes long delay with the spinning beachball. Also, many if not most contacts are duplicated, but the Find Duplicates command does not find them. I'm running Big Sur 11.4 on a 2018 15' MacBook Pro. I tried restarting in safe mode, resetting SMC and NVRAM as advised in a previous response to a similar problem on this forum, but problem remains. I have plenty of storage and RAM space, and don't have performance problems with other apps. I do have several thousand contacts, which would go down substantially if I could eliminate duplicates. Help would be much appreciated!
MacBook Pro 15″, macOS 11.4