Hi,
Welcome to Microsoft Community!
Per your description, it seems that you would like to automatically append data to an existing SharePoint list. (If this is not what you mean, please point out.)
Given this situation, based on my test and experience, there might have no out-of-box way to automatically update Excel data to the existing SharePoint list, however, I 'm trying to test again in Access which link the data to SharePoint list, if you are willing, you can see my steps:
- Create a SharePoint list> then go to Access> click External Datatab> New Data Source > From Online Services > SharePoint List.
- Once I update the Access data, it will automatically update to SharePoint list.
More details please see Import, link, or move data to SharePoint
Update some data in Access:
If this does not meet your scenario or there has any misunderstanding, please point out, we will try our best to help you. 😊
And we also welcome any community members who have some new ideas share here.
Best regards,
Gloria