Thanks for the feedback!
For the initial version of the Excel connector, a choice was made to work with OneDrive. If there's more interest in working with SharePoint Online, then we would like to add that functionality to the Connector.
A workaround that is possible at this time is to copy the file from SharePoint to OneDrive and work with that. We know this is not ideal, so please vote on this Idea if you find yourself implementing this workaround.
Any update on this, Our business has requires this to be working as well.
Instead of editing the file from Sharepoint and saving over the original, I'm having to make changes on a OneDrive version and push this to Sharepoint. I've tried various methods, including Getting the file from Sharepoint, saving to OneDrive, then editing the OneDrive version, but this seems to break the fields in the 'Insert Data' connector.