FYI, You can make QBO files from csv files. The QBO are text files that use the "OFX Banking Specification" (see

https://financialdataexchange.org/common/Uploaded%20files/OFX%20files/OFX%20Banking%20Specification%...

DIscover card QBO files have a standard header with basic info about the file, a series of statements using the OFX <STMTTRN> </STMTTRN> pairs, and a footer with some OFX closing tags for the file.

A straightforward way is to import the CSV file into a spreadsheet and create a series of functions to setup the <STMTTRN> </STMTTRN> lines. 

The header and footer info can be setup in a another spreadsheet tab.

The three parts (header,<STMTTRN> </STMTTRN> statement line, and footer) can be copied and put in a text file that is saved with the extension ".QBO".

Before importing your newly created QBO file, backup your QuickBooks file. 

Hope this helps,

John