Hi Eduardo, I know it can be frustrating, and checking your current website I noticed you didn’t find a solution, I don’t work for Webflow but I did a webpage in spanish that requires me changing the Add to cart text.
Thing is, seems to be a bug in webflow interface that doesn’t show you that at the end right side of “default text” and “waiting text” option, should show a pencil to edit the field… IS invisible in your picture just go with the mouse a little bit to the right of that field
(where is the * Default text box inside Add to cart Buttons Settings)
I hope it helps, If not, feel free to ask