DOTS/ECS has nothing to do with geometry LODs. Those are purely optimizing CPU systems.
Even if DOTS was perfect, the GPU would still be entirely geometry throughput bottlenecked.
Yes, UE5 has a large competitive advantage today for high-geometry content. But that wasn’t something Unity claimed could be automatically solved (so Unity is in the same position as every other engine in existence apart from UE5).
The developer should have been aware from the beginning of the need for geometry LOD: it is a city building game! The entire point is to position the camera far away from a massive number of objects!