These buttons should at all times be readable, an ellipsis overflow likely removes the meaning of the text in a lot of cases.

For example on the second page of the Czech site cookies box (click "Upravit"). See also screenshot.

I included a second screenshot where I removed the Ellipsis style and overflow, to show the total length of the text in this case.

It's not a particularly long string, I can imagine this is an issue in multiple languages.