Details Panel Dynamic Exposed Variables?

This vid is interesting to watch for beginners but does leave me wondering 1 thing https://www.youtube.com/watch?v=6485d5Zoc_k
Do I need to restart UE for every change to a C++ file?

… I should probably add, I’m using a “Blueprint” project.

Every c++ change requires you to rebuild the project. At that point you should close UE entirely and build in VS. do not use the hot reload feature for UE as it doesn’t work properly and causes corruption. If TrofimovYuri answered your initial question, please mark his answer as the solution. It’s best to create new posts for new questions.