When to try it
If you mainly read and send ordinary email, connect one compatible account and check folders, attachments and sending. Use the combined list to keep personal and work addresses close together.
When to involve your administrator
Exchange and Microsoft 365 can involve shared calendars, mailboxes and delegated access that ordinary IMAP does not provide. Outlook.com requires OAuth2 sign-in. Before switching, ask your administrator whether Postosha access is permitted and how you will use any shared work tools you need.
Local Outlook archives do not transfer automatically
Connecting over IMAP loads server mail. It does not transfer local PST/OST archives, contacts, calendars or Outlook rules. Save those separately and keep Outlook until you have checked access to your important data.