How can I reuse a custom SharePoint list month over month and bulk upload 500-2000 Items each time?

Currently, I have a custom list in SharePoint with ~500 Items (or rows) and ~40 fields (or columns). The list has been customized to include things like Conditional Formatting, custom dropdowns, shading, etc.

I’d like to take the same custom list, remove the data that is in it currently, and populate the list with new data (another ~500 Items).

See below for some things I’ve tried so far: 1. I tried saving the current Custom List as a Template and then copying and pasting in new data. Unfortunately, this did not work because several of the fields I needed to copy and paste in included special characters and line breaks. Because of this, SharePoint wouldn’t let me copy and paste all of my data and instead I needed to enter the data a couple cells at a time.

  1. I tried opening my Custom List in Access and doing an import in Access from an Excel file, but Access kept disconnecting from the SharePoint site and then couldn’t reconnect. Access was also very finicky with the Excel file I uploaded – I ended up needing to download an export file from SharePoint, make my edits to the Excel download from SharePoint, and then save that file and import through Access.

  2. Creating a new list with a bulk upload from an Excel list and then recreating my Custom List from scratch. This works, but is very time consuming.

Any ideas on how I can easily reuse the same Custom list month over month?

Thank you!