Mailbox is on an exchange server, just have a pst file for extra email
storage, personal folders.
Just checking if way to launch outlook without the pst attached
No, because the PST is not attached to Outlook, it is referenced by the mail
profile Outlook is opening. Either the PST is in the profile or it is not.
You can certainly have two identical profiles, one with the PST reference and
one without, and at startup specify which profile Outlook should use.