That size landscape should be fine, ignore my suggestion, I was assuming a much larger area for 50k.
If your POI’s aren’t clustered in the same cell, it should be fine, later on you can adjust cell size and loading range to suit and also build HLODs.
Something is causing a big memory hit though, but I don’t think it would be the landscape.
What are those tall boxes ? they look like waterzone bounding boxes.