This is something I am looking in to at the moment.
Previously (in UE4) I have been able to import huuuge maps. 85x85km square maps. For whatever reason. I cannot do the same in UE5. It seems to be limited by the ram. Which makes sense.
But in UE4, I could load so much at a time. In UE5, it seems to force load everything. So I can’t even get past the import stage.
Anyway, to answer your question. Yes, you can import landscape tiles exported from something like world machine. When importing, just select tile 0,0 and it should grab the rest automatically.