Quadtree is quite suitable for such a solution to your question, but in my opinion this is an unnecessary complication. I think that the default UE streaming system is enough. Each level can contain its own necessary sets of data and at the same time be controlled by one manager. Here I just may not quite understand what exactly you want to do, but it’s just that for a large open world UE already has everything.
In any case, the concept of infinity will rest on the size of the memory, so you need to work not with infinity, but with utilization and data recycling.