How many columns does the CSV has, and what is roughly the size of the file?
I've had a requirement to insert a 3 mln file into a data table and I used the import functionality of the data type landing page. Then you can upload the file (skip validation, make sure the data always fits*), and import it.
The import took about 2 hours to complete. But the import runs on the background, so the user uploading the data doesn't have a locked session.
*) any pre-import formatting needs to be done in some other tool (visual studio code, notepad++, etc.)