When you say “waited until it is fully executed,” what is waiting?
Rendering?
Main thread?
Further physics?
Networking?
Sound?
GUI?
In general, you can create a FTickFunction instance and make sure it’s scheduled for the Main thread and run in the post-update tick group and it’ll probably be what you’re looking for.
Another option is to go through FGenericTask and add it at the end of the post-physics tick group.