Merge PST tool is used for combining multiple PST file into single PST file, It supports all the version of MS outlook including 2019 & other. The software accurately joins or merge the lots of PST files into one, including all items like emails, contacts, calendars, tasks, etc.
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: https://www.osttopstapp.com/pst-merge.html