We cannot have document folder path URLs in multiple languages for one site. The URLs are generated as per the main language of your site that creator has selected during site creation.
It means if you have selected German during site creation, you will get URLs in German language. In the images that you have shared, please check the primary language of the ...
I've managed to solve the problem. I used deprecated js library sp-pnp-js (https://www.npmjs.com/package/sp-pnp-js). Now it also works in IE11.
I had to change the lines to:
import pnp from "sp-pnp-js";
let data = await pnp.sp.web.lists.getByTitle(listName).items.get();
Set IsRequired = false, e.g.:
[DataMember(Name = "CanvasContent1", IsRequired = false)]
MSDN Source: DataMemberAttribute.IsRequired Property
Gets or sets a value that instructs the serialization engine that the
member must be present when reading or deserializing.