I'm having problems with Outlook 365 connecting with G Suite. So when I connect the outlook client via IMAP, the user has such a big mailbox that it seems takes a long time to sync each time. What is the recommended method for connecting gmail to Outlook? Is there a better way to optimize IMAP so it runs well with a big mailbox?
Try to install Google Workspace Sync for Microsoft® Outlook (GWSMO) instead.
https://tools.google.com/dlpage/gssmo/