If this is your first attempt at submitting an add-on for the Google Marketplace, it—like all new experiences—can take longer than expected as you learn and get comfortable with all of the requirements. You should expect pushback from both the OAuth team and the Marketplace team, as they are on the frontline of ensuring that end users have a positive experience installing Add-ons. Taking the time to slowly go through and make sure you have each of the elements along with a willingness to update and improve your application will surely result in the successful publication of your Add-on published in the Google Marketplace.
Alice Keeler knows a thing or two about publishing Google Workspace Add-ons to the Marketplace with over 20 entries. In this post on the Google Cloud Blog Alice shares some of her top tips for surviving the publication process. This includes website essentials, tips on artwork as well as creating your verification video. Follow the source link for these tips and more.
Source: Google Cloud Workspace Add-On Customization | Google Cloud Blog
Member of Google Developers Experts Program for Google Workspace (Google Apps Script) and interested in supporting Google Workspace Devs.