xlsx to mp3 conversion can actually mean many things with the one most common being the recovery of any embedded audio content from the spreadsheet. This should be doable with Excel, but quite often the multimedia files inside are just links to the actual files. You can always check the path, but it's often url.
Another possible way how to look on this, would be to using tools like Balabolka to generate voice/speech based on source provided in Excel spreadsheet.
You can actually find many online converters for this, but if they actually work is completely different matter.
Updated: July 18, 2023