I don’t think it supports day of week or similar. The natural language means you can add something like <% Next Friday %> and it evaluates to the journal entry for next Friday.
Thank you for your Suggestions, I have now been able to find a Solution.
I was actually searching for a Solution without a Plugin, because I sync the Graph with my Phone and need everything on there work exactly the same.
However, on @stdword Suggestion I spotted that the Journal-Title Itself has the Day in it witch got Part of my Solution.
I added the Day to the Journal Title by editing the graphs config.edn