After UE5.3, the method to set internal color is a bit different, I wrote a blog post addressing this issue: [UE5] How to Set Internal Material Color in Chaos Destruction (Unreal Engine 5.5) - Key Blog
If you mention the different of setting internal material they change after UE5.3 or 5.5 in your tutorial, that would help learner a lot. I stuck at that point for 1 hour…