Though it's a little more complicated, if you wish to manually convert Google Takeout MBOX files to PST using Thunderbird and Outlook here is a guide:

One free email client that supports MBOX files is Mozilla Thunderbird.
Microsoft Outlook to import and translate emails into PST style.

Detailed Step-by-Step Guide

Step 1: Thunderbird imports MBOX File.

Install Thunderbird (should you not currently have it).

1. Add Import Export Tool NG Additional:
   Show Open Thunderbird.
   See Tool > Add-ons and Themes.
   Get ImportExportTool NG and install it.
2. Imports MBOX into Thunderbird:*
   Choose Import Export Tool NG > Import MBOX file after right-click on Local Folders in Thunderbird.
   Choose Import directly one or more MBOX files then click OK.
   Look for and import your Google Takeout MBOX file. Thunderbird now shows your emails.

Second Step: Make Outlook the Default Email Client.
One open Outlook.
See File > Options > General and ensure Outlook is the default email tool.

Third Step: Export Thunderbird emails to Outlook.

1. In Thunderbird, select all emails you imported from the MBOX file.
2. To save individual Forward as Attachments or Save Selected Messages > EML Format right-click here.
3. Drag and drop these E-mail files into an Outlook folder or make advantage of Outlook's import capability:
   File > Open & Export > Import/Export.
4. Choose Import from another software or file and choose the folder with. eml files.

Step 4: Outlook export to PST

Outlook should be accessed File > Open & Export > Import/Export.
Choose Outlook Data File (.pst after Export to a file.
Select the folder containing your imported emails, then use the prompts to produce a PST file.

Though it can be a bit time-consuming, this approach lets you manually convert MBOX files to PST without outside applications. You have convert the bulk MBOX files into PST file format Try Out the TrustVare MBOX to PST Converter Software.