Thank you for posting your concern here on the Community page, @ggardner. Rest assured I'm here to assist you in shrinking your company data.
QuickBooks Online Advanced currently doesn't include a feature similar to the Condense Data utility found in QuickBooks Desktop. Instead, you can manage your file size by regularly deleting unused lists, archiving historical transactions, and following best practices for maintaining your QuickBooks Online file.
You can also use a third-party app to help you shrink or condense your QuickBooks Online data. You can go to the left menu and select Apps to search for one.
Furthermore, you can learn how to copy an existing QuickBooks Advanced company and overwrite a blank one. You can even select the exact time and date you want to copy the data.
If you have additional questions about shrinking a company data in QuickBooks Online, please don't hesitate to reply below. I'm always here to support you business needs.
