A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Have you tried restarting the Mac? It may seem obvious but often is overlooked. It can chase away a number of gremlins. If that doesn't put it right...
Before attempting to troubleshoot I recommend updating Sequoia. Version 15.3 now is available. That might make a difference, especially since you apparently are using the Beta Channel update for Office.
If you need further assistance please explain exactly how you went about doing this: In Excel’s Language Preferences, English is set as the application language. Unlike Word, Excel for Mac has no Language Preferences. The Language should be determined by the OS System Settings.