Bulk update SharePoint list
1. Download your source data from SharePoint into Excel
2. In your target SharePoint List, ensure any system generated columns such as the Created, Modified, ID columns are hidden.
3. Arrange the columns in your SharePoint list to match the column order in Excel
4. Change the SharePoint view to DataSheet/Grid view
5. Copy your Excel data

6. Select a single entire row in your SharePoint List

7. Enter CTRL V on your keyboard. Make sure you do this between 50 or max 100 rows at a time.
Notes
- The above method does not require Excel, you can simply copy from one list to another list using the same process. However, I find it is easier to manage copying the data from Excel.
- You may receive error notifications that some rows cannot be pasted. This is usually because your data source/spreadsheet has multiple line breaks in a cell. You can apply the Excel clean and trim functions on all of your columns prior to pasting the data into SharePoint.
Microsoft Access:
You can copy several columns (including complex columns like People columns) in Access from one SharePoint List, and paste them into other columns in a different SharePoint list without any errors/issues.


Note I have not tested the above with Choice columns.