Why not? If you don’t want to spoil your time with this manual method of Archiving in MS Outlook, then there is only one way to split your Outlook PST File in few time i.e. third party software.
One of the best Tool in my mind that is “SysTools-Split PST Software“. I also used this software when I needed to split large PST. So, I would like to suggest you this tool based on my personal experience.
Note: Run the demo version before move further.
Let me know if you need further assistance!!!
Best Regards
Barry