The legend says that a project made in UE4 can be converted to be working in UE5…
Do note that before UE5, there’s going to be UE4 4.27 & 4.28 at least. For all we know there may be half a dozen of updates to the current engine in the pipeline and UE5 might as well be a year away (or more).
If you were hoping for a Make Open World button, there’s not going to be one. You’ll still need that elbow grease.