To follow along what Malin already pointed out, Sharegate can help you achieve the desired result.
Please note that I am part of the Sharegate User Experience team so I am more aware of what is possible with Sharegate and less with other tools available. However, other tools might also be a good fit in your case. If you would like to see how Sharegate can help you, you can simply download the free trial and follow the procedure below:
1 - Before the import, go to the destination list settings (in the advanced settings) and disable the attachments.
2 - Open the tool "Copy SharePoint Content".
3 - Choose any site/list as source. It will not be used (nor will it be modified), this is simply necessary in order to get to the next step
4 - Select the desired destination site and list (where you want to import list items).
5 - Click on Excel -> Import and import your Excel file. The Excel file will need to contain an "ID" column with fake numbers in it. The other columns can be used to fill the item's metadata in SharePoint. You will also need a "ContentType" column with the content type that you want to set on the imported items. (item, issue, comment etc.)
If your data is in CSV files, you can use Excel to transform them into ".xlsx" files (which is the only supported format in Sharegate).
6 - You will be prompted with a screen that lets you choose between "Import Now" and creating a custom template.
7 - Click on Create a Custom Template and make sure you do not select the option to copy the permissions. Select the other options that you need.
If the columns in your Excel file have the same name as the columns in your destination list, you can then click on "Save and Start". If you need to map some columns or define special actions for some columns, you can go in the Metadata section.
If it is the case, I suggest you read the documentation here: http://en.share-gate.com/support/documentation/property-template.html
and here: http://en.share-gate.com/support/documentation/map-properties.html to help you get the mappings and property template done correctly.
The reason for disabling the attachments on the destination list and not selecting the option to copy permissions is to prevent Sharegate from trying to fetch this information from the source list (which in truth does not contain any information for this use-case). In any case, since you are importing from an Excel file, you probably don't have attachments and permissions to set on the imported items.
Jimmy De Santis | User Experience Guardian at Sharegate