Steps to Import Emails from OLM File into Gmail
Step 1: Configure your Gmail account for IMAP
Sign in to your Gmail account.
Once youre logged in, click the Settings icon in the top-right corner.
Click Settings.
In the Settings page, click the Forwarding and POP/IMAP tab.
From the IMAP Access section, choose Enable IMAP, and then click Save Changes.

Step 2 Add IMAP-enabled Gmail account into Outlook for Mac.
The steps to add an IMAP-enabled Gmail account in Outlook on macOS will differ depending on the version of Outlook for Mac you are using.

Steps to Add Gmail Account in Outlook 2019/2016 for Mac
Open your Outlook for Mac application, and click Outlook >Preferences >Accounts.

In the Accounts window, click the plus (+) sign in the lower-left corner, and then select New Account.
When prompted, enter your Gmail account e-mail address and password.
Now, click Allow.
In the dialog box that appears, select Open Microsoft Outlook.
Click Done to start using Gmail in Outlook for Mac.




This will help,
J Wick