Additional features, settings, or issues not covered by specific Microsoft Teams categories
Hi Shane,
Thank you for posting back.
We understand that you want to use the feature of Upload Multiple Documents in SharePoint Online, however, we’re afraid that there is no out of box way to achieve that in SharePoint Online. In SharePoint Online, you can only upload one folder at a time. If a folder with the same name already exists in the library, the upload folder will display the same error as the one you provided. There is a bit difference between SharePoint Online and SharePoint 2010.
To address your concern about the situation, we’d suggest you go to SharePoint Uservoice to provide your feedback. This is the best platform to let us hear from you and make our products and services better for you and others. At the same time, for the "Overwrite existing files" option, we’d suggest you kindly vote this UserVoice: Bring back the "Replace" option for overwriting files.
Thank you for your understanding!
Best Regards,
Sukie