There's always Spreadsheet Compare, which is Microsoft's attempt at a diff utility for Excel. It works fairly well.

https://support.microsoft.com/en-us/office/overview-of-sprea...

Why of course you open two windows one on top of another and you Alt-Tab between them rapidly to see the differences.

Not sure if serious or sarcastic because I’m sure people do that.

I do that (not just with Excel) knowing full well how ridiculous it is, but sometimes I just can't be bothered with other tools.