We never have enough time or budget to fix the data. But we have all of the above and then some to find a costly solution.
Adding another column is always an option, but if you are transforming that column to UPPER case all of the time or most of the time. Then instead of adding new column or creating a work around you should get the data changed.
Reload the data using UPPER case and make sure that all new data coming in is in UPPER case. It would be a preferred method, at least to me

Fix the data not the process.