Is it possible to bulk add items to an existing SharePoint list?
Unfortunately, it's not possible to directly import items from an Excel or CSV file into an existing SharePoint list.
Instead, you can utilize the "Quick Edit" feature to edit your list in grid view.
From there, you can copy your items from Excel and paste them into the grid view.
However, please note that this method may not work with lookup fields.
Alternatively, you can use Power Automate or PowerShell script to bulk add items to an existing SharePoint list.