We do have the option for GMB social cover creation that is in Beta testing right now. We will be releasing a new update in the next few weeks. We will let everyone know once it's available.
If you would like to become a beta tester, you can join our Social Inner Circle, as the members of that group have access to it through the Beta testing phase. To become a member you can go to www.strategicmarketer.com/SocialIC
Related Articles:
SC How to Create a Custom Template
How to Manually Upload and Update the LinkedIn Cover
Why Is My Facebook Cover Blurry
Why Doesn't the Cover for Facebook Show in the Side-By-Side Preview
Why Wouldn't the Site Images Load Up Into the Site Gallery