For now you can just raise the loop limit. In the project settings(general tab IIRC) there is a setting that will let you raise the iteration limit to ~2 billion. It will be something like 1-10 million default.
Ultimately though, you are going to want to spread your generation over the tick. So instead of doing 5000 loops immediately, freezing the FPS, it spreads it out so the FPS keeps at least a constant 20-30 while the generation processes. This slows generation time down, but lets you have a loading bar, keep the music going, etc.
Take a look at: A couple of useful macros: Loops Per Tick - Blueprint - Epic Developer Community Forums