Excel Text Case Conversion

I have an Excel worksheet in which every text entry is stored in all-lowercase. I need that text transformed to clean, ALL UPPERCASE values throughout the file while preserving every other aspect of the sheet—cell positions, formulas, dates, and numeric data must remain untouched.

Please return a new .xlsx with:
• Every previously lowercase string converted to uppercase.
• No broken formulas or altered cell references.
• The original file name appended with “_UPPER”.

A quick turnaround is appreciated, and a short note on the method you used (formula, Power Query, VBA, etc.) will help me verify repeatability in future updates.