If you want to convert Gmail to PST without using IMAP sync, you can use a dedicated Gmail backup tool instead of configuring your Gmail account in Outlook.
I used Advik Gmail Backup Tool for this. You simply log in to your Gmail account using Google's secure authentication, select the email folders you want to export, choose PST as the output format, and start the backup. The tool downloads your emails directly and creates a PST file without syncing Gmail through Outlook or IMAP.
It's a good option if you want to avoid Outlook setup, save time, or back up a large Gmail mailbox while keeping emails and attachments intact.