Dear Catie,
Thanks for your updates and information.
The Open in Excel option in Microsoft Forms is just to download the Excel file which means that it can't sync data between Forms and Excel. To sync the data between Forms and Excel, you may upload the Excel in SharePoint manually and use Power Automate to sync the data between Excel and Microsoft Forms.
As Microsoft Forms and Access can't be synced directly, you may use Excel as a transformation place, I suggest you sync the Excel file with the OneDrive sync client first. Then open the Access file>External Data>Linked Table Manager>Add>Excel>select the Excel file in the local OneDrive sync folder and then you can use Relink and reopen the Access file to see if the data is updated. I'm afraid that this way can't be updated automatically in Access and you may need to update data by a manual action and the sync may take long time.
So I think that Excel may be not a good transformation place. I suggest you use SharePoint Online list. Then you can transfer the data from Microsoft Forms to SharePoint Online list via Power Automate, click on External Data in Access>New Data Source>From Online Services>SharePoint List>Link to the data source by creating a linked table and then you can submit the response in Teams and the data can be transferred to SharePoint Online list by Power Automate automatically and you can just reopen the Access file to see the updated data. In this way, the sync is quick by just closing the Access file.
Best Regards,
Cliff