Hi again, @JanisStier ...
So I just noticed that the directions/screenshots in the Guide that I gave you are not quite accurate...but close. As I was looking in my own Canvas environment with Studio, when I click on the option to "Share Media" and then the "Links" tab, there is not a "Create Public Link" button. Rather, the public "Link" and the "Embed Code" options are shown right away....at least in my view. So, if you also have these kinds of options, all you really need is that first one, the "Link" URL. That is the "public" link that you can put into your Google Slides presentation. In that Guide, I think you could simply ignore the screenshot directly under the "Create Public Link" heading and move to the next screenshot under the heading "View Links"...as that is what my screen looks like immediately after selecting the "Share Media" option. Are you seeing both of those options on your screen instead of the "Create Public Link"?