You're strawmanning. If invoking "Modify PlayerServiceActor to subscribe to GameTickEvents and cache latestTick" was enough to get good results, no one would be asking for advice on how to get good results.
You're not even keeping the argument straight. Which is it: is it "spellcasting" to get an LLM to generate a project plan like this, or "spellcasting" when it implements the project plan as written?