Google Takeout (Transfer)
The easiest way to transfer email and drive contents is to use Google Takeout (Transfer) (https://takeout.google.com/transfer) with your own personal @gmail.com account. Please note that Google Takeout (Transfer) does NOT transfer Google Contacts or Photos (see below for tips to save these or to export other data from your Google Account). Instructions to transfer your email and drive contents may be found here (https://support.google.com/accounts/answer/6386856?visit_id=637719745795700284-2137160793&p=transfer_content_emailstep&hl=en&rd=1#zippy=%2Cmy-drive-files-that-arent-copied).
The Google Takeout process will be straightforward if you do this, though you may need to pay for additional GMail Drive space if your Drive contents exceed 15Gb. If you have multiple Gmail profiles, be sure to first log out of your other GMail accounts, and then, login with your ATS email account prior to running Takeout to ensure you are backing up the correct account. Note: We suggest opening your personal GMail account in a Private/Incognito window, a different browser or mobile device in order to avoid conflicts between accounts.
Google Contacts
To Export your Google Contacts, login to your ATS email account, click the grid/cube near the top right of the page, and select Contacts (or login and go to https://contacts.google.com/). In the left navigation pane, likely near the bottom, click on Export. In the pop-up, select which contacts you want to export and the format that you want to export them as (Google CSV, Outlook CSV, vCard for iOS Contacts), and click the Export button. This should create a file in your browser's Download folder which can then be Imported into the account that you're transferring your ATS emails to.
Google Photos
Google Takeout (Export)
To export a copy of the contents in your Google Account for backup purposes, use Google Takeout (Export) (https://takeout.google.com/). With this option of Google Takeout, you'll be able to select specific items from your Google Account (Calendar, Contacts, Drive, Mail, Tasks, etc) and export it all as a .zip file for backup purposes. For the "Delivery Method", you can choose to receive a download link via email or connect to Dropbox, Box, or OneDrive accounts. If you choose Google Drive for the Delivery Method, and you save it in your ATS email drive, be sure to download the file to another device before your ATS email account is deactivated.
Please note that some have experienced problems using Google Takeout for large files/photos or large number of files/photos. In this case, the best solution seems to be to install Google Drive for Desktop (available for Mac and Windows - Download - Google Drive) which will map your Google Drives folder as another "disk". Please make sure you configure it in streaming mode, not mirroring mode (Use Google Drive for desktop - Google Drive Help). Then you can manually copy from Google Drive to an external storage device such as a thumb drive or external hard drive.