Hello. If you do not have duplicates, then there is no point in solving this issue.

But you can manually add the code to each page (I do not recommend this). For example, if your page address is https://magazin.aleksius.com/en/website-x5-tutorials-creating-a-website-from-scratch , then the code would look like this:

<linkhref="https://magazin.aleksius.com/en/website-x5-tutorials-creating-a-website-from-scratch" rel="canonical" />

This needs to be done for every page. But I don't see much point in that.