PST Merge Tool Merge Multiple Outlook PST Files
You can easily combine multiple PST files, I would suggest you go for try Merge PST Tool. This tool is to merge multiple PST files by email, contacts, tasks, journals, notes, and calendars Option. It merge any PST files as there are no limitation and It allows to removes duplicates PST files or merge unlimited PST files. It supports all versions of Windows and Outlook like 2003, 2007, 2010, 2013, 2016, 2019, etc.
Visit here for more info: http://www.merge.pstfile.org/
Click on Home tab, click New Items, click More Items > Outlook Data File.
Browse for the path to save the file, give it a name, and click Ok.