Receiving US-Excel file but Excel changes it to my local format (dates and numbers)

So, I work with an Excel file - basically copy&paste data from excel into a design software - when I realized that excel changes dates and numbers into the german format hence I received an US file and need them in the US format.

That's quite bs to say it gently.

Can I stop this? Google tells me to change my system to make it work, which seems quite complicated. Is there an option to stop excel from changing the document when I open it?