If you want to backup Gmail emails then, you can definitely use the Gmail Backup Tool . It is a very effective way to backup Gmail email files to PC, hard disk and webmail account. By using this tool, you can export emails from Gmail to PST, MBOX, EML and other file formats along with the same data structure.
Gmail Backup Tool is the best tool to convert Gmail to PST, MBOX, EML and other file formats along with the same data structure. This tool is highly reliable as it preserves all email contents including attachments, auto complete contacts and calendar entries that are stored in the Gmail account.
Gmail Backup Tool is an easy-to-use tool designed to backup Gmail emails in a very easy manner. This tool not only allows you to backup all Gmail account emails, but also support an email recovery process so that you can retrieve the deleted emails back once again.
https://www.syscurve.com/gmail-backup-tool.html

Split PST Tool
The Split PST tool allows to split large PST files into smaller ones, retaining an exact copy of the original. After new PST files are created, source data remains untouched - change the data completely, split it as many times as you like and save it in a different directory. The resulting personal folders can be attached to the profile or saved on disk.

If a size or a format of your PST files become too large, you may consider splitting them. This program will allow you to split PST files into separate folders and retain data and folder structure.

Split PST Tool allows you to split large PST files and save the resulting personal folders on your hard disk. After creating new PSTs, source data files remain unchanged. The tool supports splitting by different criteria such as creation date, attachment count, and so on. Use it to split large PST files of any size or when you need to move multiple personal folders in bulk.

Split large PST files into smaller ones with the help of Split PST tool. The tool allows you to redefine the destination folders and retain their structure, while splitting the source files using different criteria of your choice. Split PST is a fast and versatile option for managing large PST files.
https://www.syscurve.com/split-pst-tool.html