I've been experimenting with the Text Fragments and discovered that they are not accessible via the location. Apparently due to security concerns.

At first, I thought that something was going on on the Svelte side of things. And during my brief research I found out that some people were also wondering whether their frameworks were messing up the url. But no, it's simply how the browsers work. They just check the loaded content for the substring that needs to be highlighted and that's it. In the case of dynamic routing, unfortunately no text is going to be highlighted, even if the #:~:text= part is still present in the url.