I need to export out emails from Gmail to an Outlook PST file and it seems slow using this method—Outlook and IMAP/POP3 are kinda slow on archiving.
Is there any other method than going through POP3 or IMAP?
POP3 is not possible because, I think, it doesn't sync labels.
The only other thing is to setup Outlook to only sync specific labels (with IMAP).
Use Gmail Takeout:
This will leave you with an mbox file. Use Aid4Mail to convert that to a .PST: