If you are looking for a solution to merge PST files without duplicates, then I recommend the Advik PST Merge Tool. This tool is perfect for merging multiple PST files into one and is designed for both non-technical and technical users with its simple interface and advanced features. You can easily combine PST files of any size with this straightforward and unlimited method. It works with all versions of Windows and Outlook. You can try the demo version for free to see its features!
https://www.adviksoft.com/pst/merge.html